After two terms as Georgia's governor, George D. Busbee did what many outgoing officeholders do: he filed for his pension and hired on as lawyer with a high-priced firm.

Only in Busbee's case, the pension was based on an unusual claim. Busbee, 55, who by state law had been ineligible to run for a third consecutive term as governor, claimed that he was "involuntarily separated" from his job.

State Attorney General Michael Bowers agreed, and the state employe retirement board made Busbee the most highly paid pensioner in state history by awarding him $57,648 a year for life under a provision that allows qualified state veterans to draw full and immediate benefits if they are "involuntarily separated" from their jobs.

Now the state pension system is under fire and one of Georgia's most popular governors, who won two scandal-free terms with the slogan "a workhorse, not a showhorse," has become a pariah overnight. Cartoonists have lampooned Busbee, one portraying him as a pig rooting at the public trough.

He counts seven or eight letters daily at his downtown law office accusing him of everything from greed to ingratitude. Political observers who touted him as a made-to-order Democrat to oust one-term Republican Sen. Mack Mattingly come reelection time in 1986 are writing Busbee political obituaries.

"George Busbee, who left office as clean as a nun's habit, deserves even to be stripped of his title of honorary dog-catcher of Duluth," wrote columnist Dick Williams.

"Without this pension, the former governor would be reduced to getting by on whatever he can scrape together as a mere international lawyer with King and Spalding, whose practitioners, it is widely believed, must make do with earnings that do not greatly exceed a quarter of a million dollars a year. Each," huffed one editorial in The Atlanta Journal. Busbee has refused to comment on his law-firm earnings.

Busbee said in an interview that he has been unfairly singled out as a recipient of a retirement law that was written when he was in law school and whose provisions have been scrutinized by the state's top legal officer.

"Are you going to draw your Social Security whether you need it or not?" Busbee asked. "The newspapers are attacking me and should be attacking the system. I'm looking for vindication in court."

Busbee mailed back his first monthly pension check for $4,804 and ordered the state to hold future payments until a court rules on the benefits.

Two lawsuits have been filed by individuals challenging Busbee's pension. The 13,000-member State Employes Association has raised more than $6,000 to pay for a possible third lawsuit. "It is difficult to understand how an official elected for a definite term could claim involuntary separation," said association President Ronald Masters.

The retirement system would allow Busbee to draw an estimated $1.2 million (should he live to age 75) from a fund into which he paid $30,000 during 28 years of government service--18 of those as a state legislator. He made $60,000 a year as governor.

Critics say he also boosted his retirement $14,000 a year by claiming as government service time 11 months of unused vacation and sick leave, through a bill that passed early in his administration.

Had Busbee waited until he is 65 to collect his pension, he would have drawn about $29,000 a year under a new retirement law. But he filed under an old provision that provides full benefits to state employes with 27 years and 7 months of service. The controversial provision, which affects more than 300 workers, doesn't apply to employes hired after 1972.

A counterpoint to the Busbee controversy is the case of Lester Maddox, a former segregationist whose four years as governor and four years as lieutenant governor do not qualify him for a state pension. Maddox is now destitute and cancer-stricken, and his plight has prompted a black civil rights activist, state Rep. Hosea Williams, to advocate a pension for him.

While Maddox had once waved a gun to keep blacks out of his restaurant in the 1960s, Williams said he also had championed the poor. "He's the only governor I know who was poorer when he left office than when he took office," Williams said.

If Busbee wins his pension fight in court, friends say he is contemplating giving up the pension as a gesture to voters. "The only thing I can do is be right, then be magnanimous," he said.