Vienna — To the Communist East Europeans, an erstwhile ally, China, is looking more and more like a prodigal coming back - if not to the fold, at least close enough to talk in a comradely way over the gate.
Their view is based on:
* An assessment that after years without results, the Sino-Soviet talks have lately begun to reach toward a more meaningful plane.
* Increasingly active moves made by China this year to restore links with Eastern Europe. Such ties have been in abeyance for almost two decades.
According to well-qualified China-watchers in the area, a parallel process is slowly taking shape in East Europe and is developing more substance than at any other time since Moscow and Peking's first tentative probes of each other in the 1970s.
These sources see it as a deliberate, carefully conceived move by China to improve relations and its standing with the Communist world in order to bring to a close a long period of profitless isolation from almost all the Communist parties in power.
Peking, these observers say, is also aware of the uncertainties implicit in its new Western relationships. It is concerned, therefore, to establish an East-West balance by reaccommodating itself with natural ideological allies.
The East Europeans had no political option but to back the Soviets in their split with the other Communist giant at the start of the 1960s. They have continued to back the Soviets.
But no matter how sharp the polemics became, the politically farsighted among the East European leaders have never excluded some future Sino-Soviet rapprochement. They expected, however, that warmer relations would have a vastly different tone, with Peking no longer playing second fiddle to an ideological tune orchestrated from Moscow for the whole communist movement.
Rapprochement in any wide sense is obviously not yet in sight. But the East Europeans seem confident that a new phase is approaching in Sino-Soviet relations, and they anticipate ''positive'' results from the current trends.
''The atmosphere of the (Sino-Soviet) talks has changed,'' a Hungarian commentator wrote of the most recent round in the Budapest daily Magyar Nemzet.
''Everyday (Sino-Soviet) relations are also showing signs of change,'' the daily added: ''China undoubtedly wishes to improve her relations with (all) the Communist states and the efforts are bound to have positive results.''
The first moves came last year when Chinese diplomats and journalists in some East-bloc capitals began to seek informal, social contacts with their local counterparts. This year saw the first East European tourists being guided around China. Soviet groups to China followed. Educational and sporting exchanges have been renewed, and Hungarian and East German students have entered higher education institutes in Peking. Soviet students are also expected.
The fence-mending act moved into higher gear when Chinese officials made an intensive political swing through East European capitals. Chinese Communist Party leader Hu Yaobang paid an official return visit to Bucharest, and senior Foreign Ministry and trade officials called on Bulgaria, Hungary, Czechoslovakia , Poland, and East Germany.
Senior government members from Hungary and Bulgaria have since been to Peking , promoting trade and discussing more substantial contacts in general. Although they are not yet talking contact between parties, East Europeans believe that can come.
China has also waved its olive branch in Albania's direction. For more than a decade, the feisty rebel from the Soviet bloc was Peking's only ally in its clash with the Soviet Union. The China-Albania tie frayed in the early 1970s over China's new relationship with the United States, but it was not broken off until China abruply terminated economic aid and withdrew its experts from Albania in 1978.
Albania is a small country with fewer than 3 million people. But it interests China for the same reasons it interests the Soviet Union - that is, as a potential area of influence in southeastern Europe and the Balkans, and for its mineral wealth, notably chromium. (Albania has more chromium than any other European country except Russia and ranks among the world's leading producers.)
Peking's first overture came in the spring, with a visit (on Chinese initiative, the Albanians insist) to the Albanian capital of Tirana by Chinese trade officials and specialists. The sequel was a protocol signed in Peking Oct. 4 by Albania's deputy trade minister, Pajtim Ajaza. It hews to the former pattern of Albanian chrome exports (largely) in return for Chinese cotton and other staples, as during the ideological honeymoon.
Albanian diplomats here insist it is no more than a standard trade agreement. ''We will trade with any country which respects our independence and on equal terms,'' one said. He cited a series of new trading ties with almost all West European countries now, including West Germany, with whom it does not yet have diplomatic relations.
The West Germans have, for example, paid for chrome with equipment that enables the Albanians to develop an enrichment plant that the Chinese left incomplete.
The Albanians scorn suggestions that the new agreement includes spare parts for earlier arms supplies. After the war they built up their armed forces with a hodgepodge of captured German weapons and Soviet supplies, augmented later by the Chinese.
These weapons have long since become obsolete and China has yet to modernize its own production. Meanwhile, Albania has begun to manufacture the smaller arms it deems most suited to its territorial situation and defense needs.