A top Soviet news commentator and a prominent Soviet economist were among two groups of Russian visitors to Harvard last week.

The commentator, who professors here said is regarded as the "Walter Cronkite of Soviet television," was here to talk with several faculty members and to visit several Boston schools for a documentary on the problems of court-ordered busing in Boston.

Valerian Zorin met with several members of the Russian Research Center, including director Adam Ulam, professor of Government, and associate director Edward L. Keenan, master of North House.

Stanislous Menshikov, a Soviet economist who is working for the United Nations, visited here with several members of the Academy of Sciences of the USSR, including the director of the Institute of Mathematics and Economics.

Menshikov met with Wassily W. Leontief, Lee Professor of Economics, to discuss some work Leontief is doing for the United Nations.

Harvard used to be part of an annual exchange program between Soviet and American graduate students.

Keenan said yesterday that since the last Russian student to attend Harvard as part of the exchange defected to the United States, Soviet officials are reluctant to allow students to come here.