The NAACP board of directors stripped Chairman Margaret Bush Wilson of all but ceremonial powers today and asked her to resign after deciding that her unilateral suspension of Executive Director Benjamin L. Hooks was improper, unwarranted, arbitrary and embarrassing.

Only one of 51 members of the 64-person board who attended a three-hour meeting at the organization's national headquarters here opposed the actions. About 100 local NAACP members stood on the street outside singing freedom songs, shouting "We Want Hooks," and calling for Wilson's ouster.

The board affirmed Hooks as the organization's chief executive and directed Wilson not to interfere in daily operations, dispense contracts, make non-emergency major expenditures or direct staff members without his approval.

The board also decreed that the chairman "shall not act as a spokesman for the NAACP" and took from Wilson the traditional honor of giving the keynote address at the NAACP's national convention, which this year is scheduled to start July 11 in New Orleans. Board Vice Chairman Kelly M. Alexander Sr. of Charlotte, N.C., who called today's meeting, will give that speech.

Wilson learned of the action when she returned to her St. Louis home from Chicago, where she had addressed a meeting of black fraternity and sorority leaders. She told the Associated Press, "That's very interesting, but I don't propose to comment on their action."

Today's action appeared to remove most of the structural underpinnings of an often bitter power struggle that has drained the energies of the nation's oldest and largest civil rights organization. Its membership has declined in recent years, and its effectiveness and direction have wavered since the many landmark civil rights victories of the 1960s.

Speaking after the meeting to a cheering crowd outside the NAACP's headquarters building in Brooklyn, Hooks said that he considers himself vindicated.

"I hold no animosities. I bear no grudges. Revenge, and what we call in the South 'getting back,' is not a part of my character," said the 58-year-old Baptist minister and lawyer from Memphis who succeeded Roy Wilkins as executive director in 1977.

"I will work harder than ever before to keep the association the flagship civil rights organization in this nation and to make it stronger, far more effective and to give it an outreach far greater than it has ever had before," he said.

The meeting was called shortly after she notified Hooks by letter May 18 of his indefinite suspension. She alleged that he had been insubordinate, conducted himself improperly and failed to cooperate with her efforts to obtain undescribed information about organization operations.

The suspension stunned board members, none of whom had been consulted, and brought thousands of letters and telegrams from branches around the country. Most of them expressed support for Hooks.

Wilson, generally credited as being an astute board politician, tried to quell the opposition, first by calling for a special board meeting June 11 near Chicago. But other board members did not want to wait that long. She then reinstated Hooks Thursday, almost as abruptly and unilaterally as she had suspended him.

By that time, however, 45 board members, including many considered close to Wilson, had pledged to attend today's meeting--even more did. Board member Nathaniel S. Colley of Sacramento said that no one spoke in Wilson's defense at the meeting and that the sole dissenting vote was cast by Frances L. Murphy of Buffalo.

Today's actions did not seek to remove Wilson from the board. Colley said that the board does not have such authority, but most board members clearly believe the major charge made against her for six years, that she has been trying to run the organization and has impeded its progress.

Wilson had contended that Hooks is an ineffective manager, that the NAACP has a poor reputation in the philanthropic community and that it is not serving its members well.

"I think it today's action leaves her position untenable," Colley said. "What can a chairman do," he added, "when over 50 members of the board are determined that she doesn't speak for us?"

Wilson faces reelection for her at-large board seat in December, and board officers are elected each January.

When Wilson suspended Hooks, she installed general counsel Thomas I. Atkins as acting executive director, and Atkins signed telegrams contending that today's meeting would be illegal and calling instead for the June 11 session.

"Since Mr. Atkins accepted the position of acting executive director . . . it's impossible for the fallout not to hit him, too," Colley said.

Hooks said that there are no major ideological differences underlying his problems with Wilson. He termed his suspension "a most serious crisis" that could have destroyed the NAACP.

Special correspondent Lillian Calhoun reported from Chicago that Wilson told her audience that the NAACP "is an organization of stature, of integrity, of dignity, of discipline and civility" and that "as chairman of the board . . . one of my responsibilities is to hold these standards high."

She called the current dispute "an internal matter" and "pretty small potatoes" and said that it will remain an internal matter "as far as I'm concerned." She did not refer to Hooks by name.

Calling for "statesmanlike leadership" and a "vision of greatness" for the NAACP, which she said she holds, she added, "I expect every other officer and staff member to do the same."

[The audience gave her three standing ovations during her address. Conference chairman Ozell Sutton of Atlanta and Mayor Johnny Ford of Tuskegee, Ala., who chairs the national black mayors organization, were among those who rushed forward to embrace Wilson when she concluded.]