Peking — China's stress on improved relations with Western Europe follows the recent warming trend in its relations with the United States and Japan. During his just-completed tour of France, Belgium, Denmark, Sweden, Norway, and Italy, Chinese Premier Zhao Ziyang repeatedly explained China's ''open door'' policy and its eagerness to increase trade and investment, especially joint ventures with foreign companies.
His appeals during the 18-day visit were almost identical to those made in the recent past to government officials and businessmen in Japan and the United States.
''I told them that China wants to cooperate with foreign countries -- not only in major construction projects such as energy, transportation, and telecommunications, but also in the wide-ranging technical transformation of its existing enterprises. . . .
''We are not only willing to expand commodity trade with foreign countries, we also attach great importance to importing advanced technology and making use of foreign funds,'' he told the New China News Agency on the flight back to China.
Zhao's hopes for increased trade with Europe are also linked to China's disappointment with the relatively meager economic results from its Washington connection, a Western diplomat here says.
''What the Chinese want is a fallback position with the Europeans in case there are further problems with the US,'' he said.
The Reagan administration's recent difficulties in getting congressional approval for the transfer of nuclear technology to China is a case in point. Zhao pointedly told a press conference in Paris shortly after he arrived on May 30 that China had already reached an informal agreement with France for the supply of nuclear equipment for a nuclear power station near Canton. US companies are also bidding for a share in the roughly $20 billion project.
Premier Zhao has also urged European businessmen to be more competitive with the US and Japan if they want to take advantage of the opportunities China has to offer. Observers here add that the Chinese would like to do more business with Western Europe in order to diversify their sources of advanced technology and to avoid becoming too dependent on Japan and the US.
In addition to fostering competition among the major industrialized states for a share in the China trade, observers here also note that China's approach to international economic relations has become more market oriented and nonideological in the past few years.
''In the past, they had a more political approach,'' a French diplomat said. ''Now they tend to separate politics and economics.
''For us, this is the main lesson of Zhao Ziyang's trip to France. Business is business,'' he said, quoting Zhao himself. ''The time has passed for doing business merely out of friendship.''
This more apolitical approach has irked some of China's oldest European friends, particularly the Scandinavian countries which extended diplomatic recognition to China shortly after liberation in 1949. One Scandinavian diplomat pointed out that despite his country's warm and longstanding relations with China, the two-way trade was a fraction of China's trade with countries with whom it has no diplomatic relations -- Indonesia and South Korea (through Hong Kong).
Many observers here agree that China is in a good bargaining position. Unlike many developing countries, China has a high credit rating. It has about $15 billion in foreign-exchange reserves and tends to pay its debts on time, if not early. The government is rapidly liberalizing its terms for foreign investment and is aggressively seeking new markets for two-way trade.
Zhao's trip made him the first Chinese leader to meet with the leaders of the European Community in Brussels, where a commission has begun negotiations on a new economic agreement with China that will broaden the commercial accord signed in 1978. Imports and exports between China and the Community amounted to about $ 4.8 billion last year, with a slight imbalance in China's favor.
Zhao signed no major agreements in Europe, though he did initial several accords with France and Belgium, giving legal protection to business investments and preventing double taxation.
On the political side, Western diplomats here say the trip reflected China's determination to pursue a foreign policy independent of the two superpowers. Zhao consistently called for an end to the nuclear arms race, even while recognizing France's rationale for an independent nuclear force. He laid equal blame on the US and the Soviet Union for accumulating ''95 percent'' of the world's stockpile of nuclear weapons. And he called for a strong and united Europe which would make a natural diplomatic as well as economic partner for China and help bring about world peace and stability.
Referring to a potential partnership with Western European nations, a front-page editorial in Monday's People's Daily, the official voice of the Chinese Communist Party, said, ''We have no conflicts of interest between us, and there are no major issues to be solved.''
The editorial also noted that the two have complementary interests, pointing to Europe's advanced technology and large amounts of capital and China's rich natural resources and big market.
Western European diplomats here do not disagree with Zhao's general assessment of the potential for cooperation between Western Europe and China. But they point out that in the past several years, after a flurry of mutual visits by business leaders and government officials, there have been few concrete results in terms of trade and investment. The problems lie with the scale of China's economic development needs, the difficulties of doing business in a bureaucratic and centrally planned economy, and inflated expectations on both sides.
The Chinese premier omitted visits to Britain and the Netherlands. Relations with Britain are at a sensitive stage because of talks over Hong Kong. And relations with the Netherlands were only recently reestablished after the Dutch agreed not to sell more arms to Taiwan.
Premier Zhao is now touring Jiangsu Province and is scheduled to return to Peking today. Tomorrow Pieter Dankert, president of the European Parliament, is to arrive in Peking for an official visit.
China's recent economic reforms aimed at attracting more foreign business to certain ''special economic zones'' may remedy some of these problems, observers say, but the time required for businesses to get established in China will still be lengthy.