A federal judge here upheld yesterday the operation of share-draft accounts - which are, in effect, interest-bearing checking accounts - by credit unions.

The ruling came in a suit brought by the American Bankers Association challenging the authority of the National Credit Union Administration in approving the share-draft programs. Under present law, checking accounts in banks pay no interest, but credit unions offer up to 7 percent on share drafts.

Some credit unions have been offering share drafts on an experimental basis since 1974 Last Dec. 8, the NCUA issued final rules regulating such programs. The bankers' group filed suit the next day.

U.S. District Judge Aubrey E. Robinson Jr. said credit union members traditionally have had various ways to withdraw funds from their share accounts, and that share drafts "are simply a variation on established methods."

Robinson also pointed out that Congress has been aware of the share draft program for several years and put no testrictions on the use of such programs in recent amendments to the credit union act.However, he said there are several pieces of proposed legislation before Congress now concerning the use of credit union share draft powers.

He added that if access to credit union accounts by means of share drafts is to be proscribed, "it must be proscribed by the legislature" instead of the courts.

According to records filed in the case, there are 22,000 credit unions across the country that may offer such accounts. The bankers' association represents most of the nation's 14,000 banks.

The bankers' group claimed in its suit that the experimental share draft accounts in approximately 600 credit unions contained $316 million that could otherwise be in bank checking acounts. Banks had about $270 billion in checking account deposits in September.

Credit Union National Association Inc. Chairman Jim Williams commented. "We are extremely pleased with this decision which enhances the ability of credit unions to continue to lead the way in the improvement of financial services for consumers."

Francis X. Shea, senior vice president of Chase Manhattan Bank, which processes many of the drafts, said, "As a provider of services to all types of financial institutions, we are pleased with a decision . . . Share drafts are a convenient means of affecting remote withdrawal of funds from a credit union member's ascount."