In the midst of what are believed to be delicate negotiations between China and the United States on American arms sales to Taiwan, President Reagan has decided not to sell advanced jet fighter planes to Taiwan. But the United States has affirmed it will continue to sell the less sophisticated F-5E jet and other defensive weapons to the island state when needed.
The decision was announced in Washington Jan. 11. According to State Department spokesman Alan Romberg, it had been relayed to China by US Assistant Secretary of State John Holdridge, who arrived in Peking Jan. 10. Mr. Holdridge was in China to discuss a range of issues with Zhang Wenjin, China's deputy foreign minister.
The State Department announced the US had concluded that Taiwan's defense needs could be met ''for the foreseeable future'' by replacing older aircraft with comparable fighters and by extending the F-5E co-production line in Taiwan.
Taiwan had earlier sought more advanced FX fighters. China's concern that President Reagan might act on campaign proposals to step up arms supplies to Taiwan had brought growing friction to the Peking-Washington relationship.
Mr. Romberg said the State Department, the Defense Department, and intelligence agencies had concluded that ''no sale of advanced fighter aircraft to Taiwan is required because no military need for such aircraft exists.''
The announcement came at a time when both China and the US were believed to be eager to reach a compromise that will safeguard cooperation between the two countries in their global strategic confrontation with the Soviet Union. For both sides there has been, to borrow a phrase frequently used by Secretary of State Alexander M. Haig Jr., ''the bottom line.''
For the United States, the bottom line has been the freedom to continue to supply ''selected defensive weapons'' to Taiwan. The Reagan administration may be able to compromise over what kind of weapons it will sell Taiwan. But it cannot, without abrogating or amending the Taiwan Relations Act, discontinue the sale of all weapons to Taiwan, nor set a time limit on such sales.
The US does not know what China's bottom line is. The Reagan administration first assumed China would turn a blind eye to US arms sales to Taiwan if these sales did not include sophisticated new weaponry such as a new generation of supersonic jet fighters.
The debate in the early days of the Reagan administration was over whether Washington should sell Taiwan a new fighter such as the F-5G or a downgraded version of the F-16.
Nearly a year after Mr. Reagan's inaugural, however, the Sino-American dispute over arms sales to Taiwan has escalated to the point where, in public, at least, China was saying that the United States should not sell any arms to Taiwan at all. In private, it is understood to be pressing Washington to scale down its arms sales progressively and eventually to discontinue them altogether.
The justification for these demands is that China has offered Taiwan a generous nine-point plan for reunification that will permit Taiwan to maintain its own autonomous government and its own armed forces.
In an interview with the Japanese daily Sankei Dec. 23, Liao Chengzhi, vice-chairman of the National People's Congress and a member of the Communist Party's Central Committee, took these proposals a step further by saying that the Chinese Communist Party had ''definitely decided'' not to try to liberate Taiwan by force and that this decision ''will never be changed.''
Mr. Liao spoke Japanese at this interview. Sankei Shimbun's representative was specially invited to Peking for the interview, obviously aimed at the Taiwan authorities, since Sankei is the only major Japanese newspaper to have a bureau in Taiwan and is widely regarded as pro-Taiwan.
Mr. Liao also said that China opposed US arms sales to Taiwan because it was a continuation of a ''two China policy'' and ''was an obstacle to the reunification of China.''
''There is no relationship between arms sales and the maintenance of armed forces by Taiwan,'' Mr. Liao said. The US position, however, has been that if Taiwan is to be free to have its own forces, it should be free to decide from whom it is to buy arms.
Can Peking and Washington work out a compromise that shows reasonableness without offending principles? The Holdridge mission, together with the State Department announcment from Washington, seem to be attempts at least to try.