The San Diego Urban League is suing Clarence M. Pendleton, chairman of the U.S. Commission on Civil Rights, alleging that he improperly wrote league checks totaling more than $10,000 to himself on the day he resigned as the league's director to work for the commission.

The suit, filed Tuesday in San Diego Superior Court, contends that Pendleton, who was authorized to sign single-signature checks for the league in amounts less than $1,000, wrote 10 checks for $999 and one for $624.

The checks allegedly were written to cover 69 days of unused vacation that Pendleton claimed were owed him. The suit alleges that the league later determined that much of the vacation time claimed had been taken and that Pendleton had been paid previously for some of the time.

Pendleton, who served as the league's executive director from 1975 to March, 1982, was unavailable for comment yesterday.

The suit accuses him of "oppressive fraud and malice" in the use of league funds. It asks the court to order Pendleton to repay $10,614 and to account for unspecified expenditures of $5,000 or more, which the league says it knows little about because Pendleton took the records when he left.

The suit also asks $200,000 in punitive damages. At the time Pendleton left the league, his salary was about $40,000 a year plus $14,000 for miscellaneous expenses, according to league officials.