A one-time acquaintance and classmate of the new Soviet leader yesterday cautioned a Coolidge Hall audience against expecting Mikhail S. Gorbachev to institute "radical reforms" in Soviet society.

"Gorbachev will do everything for the benefit of the regime," said Fridrikh Neznansky, a Russian emigre who spoke through an interpreter. "He is not a white knight to save the people."

Neznansky, who left the Soviet Union in 1978, attended the Moscow Law Institute at the same time as Gorbachev, from 1950 to 1954. Now an editor at the emigre journal, Possev, Neznansky spoke at the Russian Research Center about Gorbachev's "formative years" during and soon after law school.

Lip Talk

"It is not the leader now that matters, but the group that put that leader there," said Neznansky, adding that the upper echelons of the communist Party elected Gorbachev, and "through his lips they will meet world problems with Reagan at the summit."

Gorbachev today begins his seventh month as general secretary of the Communist Party.

Neznansky, who worked for 15 years in the state prosecutor system and for an additional nine as a criminal investigator in Moscow, said he knew Gorbachev at law school, through conversations and mutual friends, and later in the military.

From 1954 to 1958, their professional paths crossed in the Soviet city of Stavropol, where Neznansky was a prosecutor and Gorbachev served as an area supervisor for the Communist party.

Neznansky said the career of the new general secretary of the Communist Party did not begin "in a nice way."

He related an anecdote about Gorbachev and a law school friend going out to have a beer, explaining that Gorbachev kept filling his friend's glass until the friend had become so drunk that he had to be taken from the table.

At a subsequent meeting of the school's party organization, which the friend led, Gorbachev stood up to denounce his companion's drunken behaviour. Soon after, Neznansky recalled, Gorbachev became the council's new organizer, displacing his drunken friend.

"That's where his career to the Kremlin began," said Neznansky.

During a question and answer period, Neznansky fielded inquiries from the crowd of 90 on a variety of areas concerning Gorbachev and the Communist Party.

Responding to one woman who said she empathized with Soviets who feel threatened by President Reagan's often harsh anti-Soviet rhetoric, Neznansky said, "President Reagan is the first president to understand the essence of the Soviet-Totalitarian system."

"You should not let pass all these acts of the totalitarian system which basically follow the Leninist tact of conquering the world for socialism," he cautioned.

Of the party, Neznansky said Soviets are "all subordinates to one master--the Communist Party." He added that Gorbachev will institute what reform he can, such as the ongoing anti-alcohol campaign, while maintaining the party as the leader of the country.

Neznansky suggested, however, that seemingly minor attempts at reform may set the groundwork for the next generation of Soviet leadership to make substantial changes in the Soviet system.