President Nicolae Ceausescu of Romania conferred with Soviet President Leoid Brezhnev all day yesterday but apparently failed to ease Soviet concern about China's intrusion into Eastern Europe through its relations with Romania.

A communique issued after the meeting at Brezhnev's Crimean resort on the Black Sea was unusually terse, underscoring the strained relations between the two Warsaw Pact allies.

Ceausescu flew to the Crimea yesterday morning, only nine days before the scheduled visit to Romania of Chinese Communist Party chairman Hua Kuo-feng.

Although Soviet leaders have been irked over the years by Ceausescu's independent diplomacy in distant parts of the world, Hua's forthcoming visit has touched an especially sensitive nerve because it is an unprecedented display of Chinese interest in the region regarded as vital by the Kremlin.

After his five-day visit to Romania, Hua is scheduled to spend seven days in nonaligned Yugoslavia which is also ruled by a Communist government. The purpose of these visits according to diplomats here is to demonstrate Peking's support for the two Communist countries which have frequently been subjected to Soviet pressure.

Hua's visit to Bucharest is particularly disquieting to Moscow. The Chinese have been sharply critical of the Warsaw pact, which they view as a tool used by the Kremlin for expansionist policies.

By forming a firm alliance with China, Moscow's arch-enemy, the Romanians are believed to improve their position to resist Soviet pressures for greater integration within the military alliance. Peking's assistance in this effort is viewed as running parallel to American efforts to weaken the Soviet bloc.

Although officials here privately describe Ceausecu's diplomacy as a test of the limits of Soviet tolerance, the Soviets apparently do not want to engage in open polemics with Bucharest, perhaps out of fear that Romania might be pushed into following the Yugoslav example and breaking out of the bloc altogether. Nor do the Soviets, it is said here, entertain the idea of making Romania another Czechoslovakia by sending in Soviet troops, especially since the Romanians are considered likely to fight any invading force.

Without open polemics, the Soviets are showing their annoyance by increased anti-Chinese propaganda.

Yesterday's communique made no mention to Chinan although China is believed to have been the principal topic of discussion. Nor was there mention of the word "socialism" or other standard phrases normally used on such occasions.

Clearly at Romanian insistence, the communique instead spoke about the need for "all peace-loving democratic forces" to rally "in the struggle to observe the inalienable rights of the peoples to freedom and independence."

The lack of any display of cordiality was in sharp contrast to the tone to similar communiques issued after other Warsaw Pact leaders visited Brezhnev's summer home earlier this summer.

In all previous meetings, Brezhnev conferred alone with each guest. Yesterday's talks however, included the foreign ministers and key security advisers of both presidents.