NEW ORLEANS, Nov. 28--A federal court ruling with far-reaching effects today knocked out a Louisiana law banning sports competition between white and Negro athletes.

The law prevented teams with Negro players from meeting all-white squads in events such as the Sugar Bowl.

Although not concerned in the case, filed by Negro boxer Joe Dorsey, the Sugar Bowl could be the chief beneficiary of the ruling.

The Sugar Bowl has been searching for an opponent for top-ranked Louisiana State in the New Year's Day football game. The sports segregation law narrowed the field to a handful of teams. Among them was the Air Force Academy, which frowned on the sports segregation law and all but eliminated itself from consideration.

Sullivan Acquitted

BOSTON, Nov. 28--New York Ranger forward George (Red) Sullivan today was acquitted of assaulting a fan last March in a Boston Garden brawl which developed from a televised National Hockey League game between the Rangers and the Boston Bruins.

Sullivan had been accused of attacking Stephen Tavila of Arlington.

Municipal Court Judge Elijah Adlow listened to testimony of both men and said:

"It's too bad we can't have hockey games without a lot of abuse.

"I find him not guilty."