The National Association for the Advancement of Colored People voted today to strip its name from its longtime civil rights ally, the NAACP legal Defense and Educational Fund.

The overwhelming voice vote came on an "emergency resolution" offered on the opening day of the NAACP's 70th annual conviction here.

The action was the product of an acrimonious dispute that had been building between the two groups since 1957 when. under pressure from southern congressmen and the Internal Revenue Service, they were forced to separate for federal tax purposes.

Few people however, were aware of that separation. As a result, for the past 22 years the NAACP and the fund (LDF) often were thought of as the same group. Donations intended for one often went to the other, and that was the essence of the dispute that led to today's vote.

"The LDF wrongfully has been collecting money off our name," said Dr. H. Claude Hudson, a ranking member of the NAACP board. "The only reason we didn't bring this dispute to the public before is that we didn't want to show that there was a crack in the civil rights movement."

"But," he told the convention delegates, "these people have treated us with so much disrespect - with so much treachery. This treachery we should not tolerate any longer."

Specifically, the approved resolution calls upon the NAACP board to take appropriate action - including litigation if necessary - "to withdraw and revoke permission previously granted to the NAACP Legal Defense and Educational Fund for the use of the initials 'NAACP' in its name, publications, publicity, activities and solitations."

NAACP leaders, including Benjamin Hooks, the organization's executive director, said they hope the LDF will accept the convention's ruling without a legal confrontation that, they said, could severely weaken civil rights efforts at a time of increasing challenges to past civil rights gains.However, several NAACP leaders said privately that they believe such a confrontation is unavoidable.

"The NAACP Legal Defense and Educational Fund has been our name for 40 years," said Jack Greenberg, director-counsel of the LDF who was reached at his office in New York City.

"It is our name as much as it is their name," Greenberg said. "I think it is mindless and destructive for someone else to pick it up and exploit it. It would be harmful to the civil rights movementt."

Nonetheless, Greenberg said he, too, would go to court to keep the NAACP name in his organization' title.