The Soviet Union will send a high-level diplomatic mission here next month in the hope of getting Chinese officials to resume political talks for the first time in nearly three years, according to European diplomatic sources.

Peking, however, so far has refused to commit itself to any discussions or even to acknowledge the coming Russian visitors as official guests, the sources said.

Instead, the Russians will come as private guests of the Soviet ambassador here. The mission will be headed by Deputy Foreign Minister Leonid Ilyichev, who was the chief Russian negotiator at the last round of Sino-Soviet talks before Peking suspended them in late 1979.

Once here, Ilyichev, who would be the highest ranking Soviet official to visit the Chinese capital for years, hopes his visit will be seen as a sign of good will inspiring Peking to invite him for official discussions, said the sources.

Peking, which broke off all top-level government dialogue with Moscow after its December 1979 invasion of neighboring Afghanistan, publicly disclaims knowledge of the planned visit, while it privately plays coy with Soviet diplomats doing advance work.

Nevertheless, it is expected to provide some forum for discussions with the influential Soviet delegation at least as an act of courtesy, the sources said.

Any talks would be preliminary and exploratory to pinpoint areas for future consideration, but would not deal substantively with the major strategic obstacles that have provoked bitter enmity between the two Communist powers for more than 20 years, diplomats said.

"The Chinese feel very uncomfortable with the high level of this visit, which was imposed on them unilaterally by the Soviets," said a European official. "But they say, 'If the Russians ask for a visa for Ilyichev, how can we refuse it?' "

Trying to exploit tensions in Sino-American relations over U.S. arms sales to Taiwan, Moscow began urging Peking last spring to normalize relations.

China, while pledging never to play "the Russian card," has taken several small steps in response to improve economic and cultural relations with the Soviets, boosting trade this year by 44 percent, inviting Soviet athletes here for sporting events and sending delegations to Moscow.

But Peking has kept its political distance from the Kremlin and ruled out any fundamental normalization until the Soviets restrain their military advances along China's periphery.

Last month, Yu Hongliang, head of China's Soviet desk, visited Moscow to test the latest Soviet overture. Sources said the Russians were unwilling to discuss the issues China considers most compelling--Soviet stationing of troops in Afghanistan and on the Sino-Soviet border and arming Vietnamese forces along the Chinese border and in Cambodia.

"The Soviets are not prepared to give up their global strategy," said a diplomat. "Until they are prepared to do so, you can't expect any substantive change in the relationship with China."

The Kremlin further angered Chinese leaders this month by hosting a visit by the Dalai Lama, the spiritual leader of 6 million Chinese Tibetans who fled China in 1959 and who has called for Tibetan independence ever since.

Nevertheless, Peking has displayed an interest in broadening its "people-to-people" relations with the Soviet Union while putting the larger strategic issues on hold.

This new Chinese moderation after years of rigid hostility toward Moscow is seen as part of Peking's overall diplomatic plan to stabilize its borders so it can focus on the task of economic modernization. Recently, China has moved to settle its boundary dispute with India while wooing its neighbor to the northeast -- North Korea -- with supplies of at least 20 newly built Mig21 jet fighters and a lavish reception for visiting leader Kim Il-Sung.

Diplomats also view the greater Chinese flexibility in dealing with Moscow as evidence of a strategy of positioning itself between the superpowers to enhance its bargaining position with both.

At the recent 12th Communist Party Congress, General Secretary Hu Yaobang called the Russians and Americans equal dangers to world peace. He further urged Moscow to take "practical steps" to reduce its security threat to China, thus advancing the cause of normal relations.

According to European diplomatic sources, the Soviets intend to project the coming Ilyichev visit as a practical step to get normalization talks started.

The plan has great propaganda potential for Moscow, which can blame Peking for perpetuating the split between the world's most important Communist nations if it fails to take advantage of such a distinguished visitor, according to sources.

In Peking, diplomats from the Soviet Union and its East European bloc have been trying for weeks to leak stories suggesting Chinese readiness to engage in exploratory talks when the Russian delegation arrives early next month.

But independent Communist sources caution that, so far at least, this is a case of Soviet "disinformation" designed to put pressure on Peking while possibly clouding important visits here this month by British Prime Minister Margaret Thatcher and Japanese Prime Minister Zenko Suzuki.

China's Foreign Ministry consistently has refused to comment on reports of imminent talks with the Russians.

"The Chinese have nothing to say about it because so far it doesn't have anything to do with them," said a diplomat. "They see this as a private Soviet affair because they haven't invited anyone."