China gave a first signal today of a possible end to an extensive, two-year purge in its bureaucracy by announcing a planned windup of the campaign against extremists in the army.

A Peking radio broadcast monitored here said "except for a few units, most of the army units can wind up the, campaign by the end of this year...and shift their center of attention in their work.

In recent weeks the campaign against followers of Mao Tse-tung's widow Chiang Chiang and her "Gang of Four" has turned to wallposter attacks against Mao himself. The army announcement appears to reflect a desire on the part of the post-Mao leadership to curtail distracting political debate and personnel shifts so that middle and lower level officials can resume full-time productive work.

During its two years the campaign has waxed and waned, but never before had the official press said that it was about to end in any major unit. In recent months, some areas have seemed to intensify criticism of the Gang, apparently to discourage resistance to some new policies such as college admissions based on academic merit rather than political reliability.

Civilian offices in many Chinese provinces have given little hint in recent weeks of any intention to curtail the anti-Gang campaign. It has been used to chastise officials reluctant to support new anti-Maoist economic policies, such as paying large bonuses to exeptional workers.

By contrast, the army, which backed the purge of Chiang Ching and other dogmatic Politburo members in October 1976, has appeared to be less influenced by Maoist rhetoric and has made known for some time its wish to put aside time-consuming political campaigns and concentrate on infantry training.

Today's broadcast said the army had won a "great victory" in its campaign against the Gang of Four. The announcement came as the government continued to rehabilitate the reputations of former party and army leaders once purged by Mao. Admiral Chang Hseuh-szu, younger brother of a Nationalist general who once helped kidnap Nationalist Chinese leader Chiang Kai-shek, was posthmuously rehabilitated the official New China News Agency announced.

An official youth magazine also printed a 1946 letter from Mao to several youths, including the son of the man who would become Mao's arch foe, Liu Shao-chi. Publication of the letter lent support to speculation that even Liu, denounced as "China's Khrushchev" in 1966, might have his reputation restored in the new political climate.

In August 1977, Communist Party Chairman Hau Kuo-feng, Mao's successor, said the screening of Gang of Four followers in central and provincial government agencies should be "basically completed by stages and in groups this year or a little later." Later speeches by Hua failed to mention such deadlines, and the campaign continued without an official cutoff.

In some areas, however, officials have complained that the meetings and reports required to keep the campaing going have taken time away from economic production. A Nov. 29 radio broadcast from Kansu Province complained of too many meetings.

A recent announcement by the Peking municipal party committee both revealed the arrest of several longtime followers of the Gang and suggested a new emphasis on economic development.

Today's broadcast set out five conditions which it indicated most army units had met in completing the campaign. They included thorough investigation of everyone suspected of links with the Gang, reorganization of the officer corps and leading groups, retoration of the pragmatic policy of "seeking truth from fact." (the favorite slogan of vice chairman and army chief of staff Teng Hsiao-ping), improvement in army-civilian relations and restoration of discipline.

The broadcast cautioned, however, that some of the "poison" left by the Gang in the minds of some people would remain even after the campaign was officially concluded.

The timing of the army announcement may have something to do with the rehabilitation of former defense minister Peng Teh-huai and with a leadership work conference now underway or recently completed. Peng was purged by Mao in 1959 after reportedly criticizing Mao's fondness for mass labor economic projects. Peng also reportedly demanded that China concentrate on modernizing its army and improving military training.

Peng's emphasis on building a professional army with modern weapons, rather than relying solely on Mao's notion of a "people's war" of militia and irregulars, has been revived lately in the face of the continued Soviet threat.