Christina Onassis, one of the world's richest women, said yesterday that she plans to marry a Russian shipping official here Tuesday. The wedding would raise the possibility of a shift of the ownership of a major capitalist business empire to the capital of the strongest communist country.

But Onassis, 27, told business associates and journalists that the control of the vast business enterprises built by her late father, Aristotle Onassis, will remain in the hands of his trusted executives led by Louis Andersen.

Onassis' announcement, coming after days of rumors and denials about her romance with Sergei Kauzov, 37, indicated that Soviet authorities have approved the marriage.

The Soviet government has traditionally sought to discourage marriages between Soviet citizens and foreign nationals. Marriage licenses in such cases are granted with extreme reluctance and after protracted deliberations.

Onassis, who owns business interests worth an estimated $500 million, was obviously an exceptional case.

Neither Onassis nor Kauzov was available for interviews. But when reached by phone at her heavily guarded suite in the Intourist Hotel, Oanssis said she was "getting married on Tuesday," that she planned to live with her husband here and possibly raise a family.

"I can live here, I'm adaptable," she said.

Although there were no news reports about the impending wedding here, rumors have spread throughout the city causing disbelief, mirth and speculations.

"I've heard that Jacqueline Kennedy Onassis is coming to the wedding," said an engineer from the Kuibishev machine plant. References to Onassis' vast fortune and the fact that her father was married to the widow of President Kennedy are aspects of the impending marriage that fascinate Muskovites.

Onassis first met Kauzov, a middle-echelon bureaucrat in the Soviet state shipping firm Sovfracht, when she visited here in October 1976, to negotiate a business deal. At the time, she was trying to arrange for Sovfracht to charter several ships from her large fleet of tankers.

Kauzov was subsequently assigned to Sovfracht's Paris office. A graduate of Moscow's Institute for Foreign Languages he is fluent in English and also speaks French.

While in Paris, Kauov quietly arranged for a divorce from his first wife Natalya. The couple has one daughter, Katya 9. Mrs. Kauzov was given custody of the child.

Kauzov, who lost one eye in a childhood accident, is described as a short man with thinning hair.

Onassis, whose previous two marriages have ended in divorce and annulment, is the only surviving child of Aristotle Onassis. Her brother, Alexander was killed in a plane crash in 1973.

No other information about the prospective wedding was available except that the couple will be married in a civil ceremony at one of Moscow's "wedding palaces". If the ceremony follows standard Moscow practice, it will last less than 10 minutes.

Beyond these facts, there is speculation concerning Kauzov's future career prospects. Onassis home here and the future ownership of Onassis shipping and real estate interests should the couple have children here.

Under Soviet laws, such offspring would automatically be regarded as Soviet citizens.

Greece, where Onassis is a citizen, do not generally recognize Soviet marriage and any children would be considered illegitimate for inheritance purposes.

Another intriguing aspect of the impending marriage is Kauzov's future employment with Sovfracht. He is said to be on an extended leave of absence. But Soviet authorities insist that all able-bodied persons must hold jobs and the refusal to hold a job can lead to legal action on charges of "parasitism."

Some Moscow journalists privately joked about the prospects of the future husband of the Greek heiress holding a $100-a-week job. But these journalist clearly relished the public excitement generated in the West over Onassis' plans to settle here at 3 time when there is widespread publicity about authoritarian impulses of the Soviet government, economics deprivations and other difficulties of daily life.

Kauzov himself has sought to dispel speculation about any financial motives in his romance.

In an exclusive interview with London's Daily Mail, he said, "Capitalism and communism have nothing to do with love."