BIRMINGHAM, Ala. (AP) _ A former Ku Klux Klansman described by a prosecutor as ''a field marshal in the streets'' during a battle between Klansmen and civil rights marchers more than nine years ago has been sentenced to six months in prison.

In sentencing Ricky Lynn Creekmore, U.S. District Judge Sam C. Pointer Jr. said Tuesday that the punishment might discourage members of other groups from contemplating violence.

The judge said that Creekmore took a substantial role in the melee March 26, 1979 in Decatur, about 70 miles north of Birmingham.

Creekmore, convicted of a misdemeanor of conspiring to deprive marchers of their rights, has a request before the U.S. Supreme Court to review the case. Pointer set Feb. 9 as the date for Creekmore to report to prison but said that could be postponed if the Supreme Court has not acted by then.

Photographs of the battle in Decatur show Creekmore, wearing an ''Invisible Empire of the Ku Klux Klan'' T-shirt, swinging a baseball bat and a tree limb at blacks and at police trying to keep the two groups apart.

Al Moskowitz, a Justice Department prosecutor, said that although Creekmore could not be called the mastermind of the Klan's alleged conspiracy to disrupt the march, ''it can be said he was a field marshal in the streets.''

Moskowitz asked for the maximum sentence of one year in prison.

Creekmore's attorney, Don Colee, asked Pointer to put his client on probation, saying that ''Rick's not proud of what he did back in '79 and '80.''

Since 1981, Creekmore has married and adopted his wife's two children, Colee said.

Two months ago, Klansman David Lee Kelso, another of eight Klan members indicted in the case, pleaded guilty to a conspiracy charge, and Pointer sentenced him to two years probation after suspending a one-year prison sentence.

In 1986, U.S. District Judge William Acker sentenced Derane O'Neill Godfrey to a year and a day in prison after he pleaded guilty.

Other Klan defendants are to stand trial next year, but have appeals of evidence-suppression rulings pending. The violence occurred as the Southern Christian Leadership Conference led a march protesting the prosecution of a mentally retarded black man accused of raping a white woman.