Sino-US understanding on Taiwan arms after all?

China has avoided, at least for the time being, a showdown with Washington over arms sales to Taiwan.

A Chinese statement made Jan. 13, as US Assistant Secretary of State John Holdridge was concluding three days of talks with Chinese officials here, was noticeably bland. It may indicate that China's leadership has decided that there is as yet no need to come to a parting of the ways with Washington over Taiwan.

''The talks covered the main aspects of our bilateral relations, including the question of United States arms sales to Taiwan,'' said a Chinese Foreign Ministry spokesman.

''International issues of mutual concern were also discussed. Further talks on a wide range of international and bilateral subjects will continue both in Peking and in Washington,'' he continued.

Mr. Holdridge himself, in his meeting with Vice-Premier Ji Pengfei Jan. 13, characterized the talks as ''useful and productive'' and thanked his hosts for having received him so cordially''despite the short notice.''

The Jan. 13 statement contrasted with China's protest the day before over President Reagan's decision to continue to sell arms to Taiwan while not selling advanced fighter planes.

Publicly, the United States has made it appear that President Reagan's decision was based entirely on an evaluation of Taiwan's own defense needs and had nothing to do with pressure from Peking.

Privately, however, it seems clear that if it had not been for the steadily escalating warnings coming from Peking, President Reagan would have gone ahead and sold a new generation of fighter planes to Taiwan, in keeping with his own campaign promises.

Thus Peking may consider that its warnings have had their effect and that although in form President Reagan made a unilateral decision, in fact he was heavily influenced by considerations about the consequences for American global strategy vis-a-vis the Soviet Union had he decided otherwise.

Peking must also consider that the Reagan decision is a disappointment to Taiwan and may well help to arouse doubts in Taiwan about the wisdom of relying entirely on American logistical support for continued military confrontation with the mainland.

Thus, if the total future amount of American military sales to Taiwan is less than before (and there is no sale of sophisticated new weaponry), an unspoken compromise could be in the making between Washington and Peking.

This could develop without a favorable open US response to Peking's demand for reduction and eventual ending of arms sales to Taiwan.

It is too early to speak of such a compromise. On both sides of the Pacific, the American commitment to Taiwan is an emotion-laden subject, and neither Washington nor Peking can afford to be seen publicly as having given way to pressure from the other side.

A determining factor in how Peking chooses to play its hand may be its evaluation of how matters will develop in Taiwan - whether Taiwan will continue its firm refusal even to allow exchange of people and goods with the mainland, whether there is any hint of new flexibility on Taiwan's part.

In the end the contradictions between Washington and Peking can be solved only when Peking and Taiwan themselves come to some sort of understanding.