China's Communist Party Central Committee has completed a crucial meeting by promoting a pragmatic economist to the top ranks of the leadership and acknowledging some continued resistance to rapid changes in policy.

The New China News Agency reported today that the 11th Central Committee's third plenary session, the most important party meeting in nearly a year, ended yesterday after reaching a number of unprecedented foreign and domestic policy decisions.

The meeting climaxed weeks of intense discussions among China's leaders that appeared to set a course toward closer ties with the capitalist West, including more experimentation with such formerly forbidden policies as seeking extensive foreign loans and sending many students abroad.

The final communique of the session called for increasing the income of peasants, who make up 80 percent of China's 900 million people. It endorsed continued criticism of erring bureaucrats, like the critiques that have appeared in wallposters throughout China in recent weeks. These central decisions appear to bear the personal stamp of party Vice Chairman Teng Hsiao-ping, who saw a few more of his closest political allies promoted to the fuling politburo during the session.

Chen Yun, 73 a veteran economist and financial expert, received the most starling promotion when he was advanced to the number five postion in the party by the delegates to the session. Chen's new position as party vice chairman puts him in front of party Vice Chairman Wang Tunghsing, the secret police expert and former bodyguard of the late chairman Mao Tse-tung. Wang has been vehemently criticized by some recent poster writers for denying people their human rights. His demotion from the fifth to the sixth spot may reflect that criticism.

The Central Committee also agreed to close down the two-year-old "National Campaign to Criticize the Gang of Four"-the Peking clique pruged in 1976 that had included Mao's widow, Chinag Ching - so that the populace can give fuller attention to the modernization of the economy. The decision indicated no softening of enmity toward the "gang," as the session officially rehabilitated several of the clique's political adversaries, such as former defense minister Peng Teh-huai and southern China leader Tao Chu.

The communique at the end of the five-day session that began last Monday hinted that some party members still resist Western-style economic reforms such as the large wage incentives Teng and Chen have proposed. The session voted to form an extraordinary 100-member central commission to inspect discipline among party members. Chen was named first secretary.

The new commission may be aimed at cleaning up the ranks of the more than 5 million Chinese who have joined the 35-million-member Communist Party since 1966, when leaders committed to the most dogmatic thoughts of Chairman Mao exercised great control over admission. The official press in the two years since Mao's death often has charged some party officials with not vigorously pursuing controversial policies, such as incentive bonuses, which Mao had criticized as creating the basis for a new elite.

Three other party leaders, all with close links to Teng or his policies, also were promoted to what has been the 23-member Politburo.No Politburo members were purged, However, in what may be an attempt to maintain an appearance of unity and stability in a leading body where opinion on some issues is known to be divided.

One of the new memberms is Teng Ying-chao, 74 widow of the late premier Chou En-lai, Chou, a popular leader, ahd sponsored Teng Hsiao-ping's program for modernizing the economy. His widow has been an active party official since 1925 and now becomes the highest ranking woman in China. Hu Yao-pang, 63, head of the party's orgaization department, also was promoted to the Politburo to join his friend Vice Premier Teng, The careers of the two have been closely linked.

Wang Chen, 70, a vice premier, was promoted to the politburo in the wake of his much publicized trip to Britain to negotiate the still undisclosed purchase of the Harrier vertical takeoff jet. Wang appears to serve as the leadership's expert on armaments, shipbuilding and offshore oil.

The promotions continue a pattern of returning veteran officials to high office who had been involved in criticism of Mao's more utopian schemes for economic development. Hen Yun appeared to lose most of what had been his considerable power in the government after 1949 when he derided Mao's ambitious Great Leap Forward with the observation: "One cnnot reach heaven in a single step." Chen's words came back to haunt him during the Cultural Revolution in the 1960s, but his results-oriented approach to the economy now reflects national policy.

According to the official New China News Agency account reaching here, Party Chairman Hua Kuo-feng apparently voluntarily diminished his claims to power as the nominal leader of the party, army and government, by endorsing collective leadership. "Any personal view by a party member in a position of responsibility including central leading comrades, is not to be called an 'instruction,' Hua said. The statement seems to prohibit the creation of another personality cult like the one that surrounded Mao, but it also might be used to limit the substantial influence that has accrued to Teng.

The communique mentioned difficulties with agriculture, which has "been severely damaged in recent years and remains very weak." The Central Committee ordered generous new incentives to raise sluggish grain production, now expected to barely exceed last year's estimated 315 million tons.

Next summer, the communique said the government will pay 20 percent more than in the past for grain it buys from peasants and will raise the prices of special categories of grain as much as 50 percent. Farm equipment prices will be cut and ruban food prices will stay the same, the document promised.