George A. LeMaistre will be elected Tuesday as chairman of the Federal Deposit Insurance Corp., the government agency which regulates thousands of state-chartered banks and insures deposits up to $40,000 in nearly all banks.

LeMaistre, a lawyer and banker from Alabama, has been one of the three directors of the FDIC since 1973. He apparently has been the Carter administration's choice to head the insurance corporation since January.

The FDIC in recent years has presided over several billion-dollar bank failures including U.S. National in San Diego and Franklin National in New York.

Although the administration has long approved of LeMaistre, FDIC sources said his election to the top job comes with little intervention on the administration's part, although Carter officials are aware he will be elected Tuesday morning.

Robert E. Barnett, the Republican - appointed chairman, said he will resign as chairman Tuesday morning and move the election of LeMaistre as his successor. Barnett's previously submitted resignation as a member of the board is effective Wednesday, so he will serve one day as a board member after resigning as chairman.

There are two appointed FDIC board members. The third member of the board, by law, is the Comptroller of the Currency. The comptroller's office oversees regulation of the nation's 5,000 nationally chartered banks.

Normally, if the FDIC's top job becomes vacant and no successor is elected, the comptroller of the currency takes over as acting chairman. But the comptroller of the currency has been an acting one since last summer.

That would have meant, Barnett said, that an acting comptroller of the currency, Robert Bloom, would have become acting chairman of the FDIC. He called it an "unusual situation."

Last week President Carter nominated John G. Heimann to be comptroller of the currency. Heimann, a former New York Superintendent of Banks, is now that state's commissioner of Housing and Community Renewal.

Although Barnett submitted his resignation several months ago, the President has not yet named anyone to replaced him.

Barnett said in a telephone interview that there would be nothing legally wrong with the acting comptroller of the currency becoming acting chairman of the FDIC as well. But, he said, for purposes of forestalling any nuisance suits by stockholders of banks of the FDIC is liquidating, it would be better to have a chairman elected by all three members of the FDIC.

When there is new comptroller and a new appointed member of the FDIC, they an "ratify" the election of LeMaistre, who is 65, Barnett said. The chairman of the FDIC is always technically elected by the board, although the President always determines who the chairman will be.

If the administration still tinks LeMaistre should head the FDIC, "this whole thing could have happened a long time ago," one FDIC source said. Since the adminstration has made no moves to block his election as chairman, it apparently still feels that LeMaistre, a Democrat appointed by President Nixon, should head the agency.

Before the was named to the FDIC is August, 1973, LeMaistre was president and chief executive officer of the National Bank of Tuscaloosa. He was a lawyer before that.