BUCHAREST, Rumania, Nov. 20— Using the occasion of a major Communist Party congress, President Nicolae Ceausescu made it clear today that as long as he is in charge, Rumania will not follow other East European countries along the paths toward democracy or capitalism.

”Some socialist countries have adopted measures with a view to increasing the wealth of some people and increasing the number of poor,” he said. ”This focus is not socialist, and we cannot admit it in any way.” Choreographed Response

In a five-hour speech constantly interrupted by delegates who jumped up, chanted slogans, applauded and sat down in unison, Mr. Ceausescu singled out no particular Eastern bloc government for criticism, prefering instead to emphasize each country’s right to pick its own political system.

But the 71-year-old President indirectly referred to widespread speculation about German reunification after the opening of the Berlin wall, noting that ”the existence of two Germanys should continue to be a reality of Europe today and tomorrow.”

He also raised eyebrows by calling for ”the condemnation and cancellation of all the accords concluded with Hitler’s Germany, practical conclusions being drawn to eliminate all the consequences of those accords and dictates.”

One consequence of the Hitler-Stalin pact of 1939 was that Soviet troops occupied the Rumanian territory of Bessarabia. Although Rumania’s Communist Government has never reclaimed what is now Soviet Moldavia, more than 90 percent of its population is still Rumanian, with nationalist sentiments one reason for recent unrest in the republic.

Most of Mr. Ceausescu’s speech today, though, was dedicated to extolling the virtues and listing the achievements of the Government since he became General Secretary of the Rumanian Communist Party in 1965.

Only on two occasions did he abandon his prepared text and raise his voice almost to a scream to insure that Rumanians were in no doubt about his opinion of those East European Governments that are veering away from Communism.

”What do we say to those who want to lead the way to capitalism?” he asked. ”What were they doing when they were in positions of responsibility? The answer is they used their jobs to block socialism and did not serve their people.” Evils of Capitalism

To underline his point, he said that the capitalist world was characterized today by unemployment, homelessness and growing illiteracy. ”Adding to all this are crime and drugs, which have become national problems in many countries,” he said.

While Mr. Ceausescu’s orthodox stance came as no surprise, the long-scheduled party congress has underlined his hard-line Government’s growing international isolation as well as its heightened sensitivity to foreign criticism .

With the exception of Yasir Arafat, chairman of the Palestine Liberation Organization, no prominent foreign dignataries were present at the opening of the party congress, and other East bloc Communist parties sent low-level delegations. Western ambassadors boycotted the occasion to protest Rumania’s human rights record.

In the days leading up to the congress, the Government also tightened its borders with Hungary, Yugoslavia and the Soviet Union to the point of turning away ordinary tourists. A French journalist was expelled last Friday, numerous correspondents from Western newspapers were refused visas, and reporters arriving here Sunday saw all their papers mentioning Rumania seized by customs officers at Bucharest airport. Master in His Own House

At home, though, bolstered by a huge and notoriously effective security apparatus, Mr. Ceausescu still appears to be unchallenged, with dissidents numbering only a score of intellectuals and disillusioned party officials whose occasional protests are better known abroad than here.

Unlike other East European countries, Rumania also seems to be largely immune to pressure from the Soviet Union. Moscow has had no troops stationed here since 1957 and has viewed Mr. Ceausescu as something of a maverick ever since he criticized the Soviet invasion of Czechoslovakia in 1968.

Further, even though living conditions have steadily deteriorated over the last 15 years, the Rumanian economy is less dependent on the outside world than that of, say, Poland because of Mr. Ceausescu’s decision to dedicate the 1980’s to paying off the country’s $11 billion debt.

”The repayment of the foreign debt is a great success of our state’s policy, and it puts an end to this country’s long dependence on foreign monopolies and financial capital,” he said today. ”For the first time in its history, Rumania no longer pays either tribute or interest.”

And although the Rumanian leader has lost much of the international influence that he enjoyed when he was viewed by the West as a critic of Moscow, Mr. Ceausescu urged the superpowers to move rapidly toward disarmament. Specifically, he called for the denuclearization of Europe by 1995 and the elimination of all nuclear weapons by the year 2000.

photo of President Nicolac Ceausescu (Agence France-Presse) (pg. A9)