Black leaders of the half million-member Seventh-Day Adventist Church in North America suffered a resounding defeat last week in their 11-year battle for a separate administrative structure within the church.

The largely white annual council of the church, at its annual meeting in Takoma Park, rejected by a vote of 190 to 53 the black leaders' appeal for a realignment that would give blacks greater control of their religious life.

The estimated 110,000 black Adventists in this country - more than 20 percent of the membership of the church in this country - overwhelmingly are members of predominantly black congregations.

In 1944, black leaders won approval from church authorities for the organization of eight black conferences - the next step up from local churches in the pyramid of the church's organizational structure. A conference is roughly equivalent to a diocese.

But the black conferences are associated with some white conferences to form the church's nine regional unions in the U.S.A. Black leaders, complaining that their needs are overlooked and their strength diluted in the overwhelmingly white unions, have for 11 years sought their own black unions. No black ever has been selected for top leadership of a union although some have served in secondary positions.

In the flow of rhetoric that continued into a late-night session at the denomination's spacious Takoma Park Church last week, the central reason for rejecting appeals for black unions appeared to be a public relations problem - the fear that the creation of all-black structures would be viewed as segregationist.

"I think that's the main point - the fear of the image it (the creation of the black unions) might project," said a church spokesman after the vote.

The image of the church as a racially inclusive body is particularly prized because a large amount of the church's mission efforts are focused on urban black areas.

One of the most moving appeals for the black unions came from Dr. Earl Cleveland, professor of theology at Oakwood College, the denomination's black school in Huntsville, Ala.

"We only ask you to let the men who know best their own people administer the affairs of their own people at the union level," he said. "It is at the union level that the control of the future of the conferences of the church in North America resides."

He pleaded with the delegates to "write us into the system . . . "We're a little tired of being called into a corner and being asked: "Well gentlemen, what is your problem?"

His remarks, greeted by murmers of assent from about 250 black non-delegates who followed the debate with interest from seats in the balcony, alluded to many private meetings over racial differences that black leaders have had with top officers of the church.

"I'm pleading with you - don't slam this door," he continued; "Don't step on us because you can, please . . . please."

The case against separate black judicatories was presented largely by Neal Wilson, 58, president of the North American Division of the church, who also chaired the day's discussion.

At the outset of the session, Wilson remarked that "many minds are already made up" on the question. But he explained that it was on the agenda because it was "a complicated, complex, serious even sacred issue."

Church officials had distributed to delegates before the meeting a one-page mimeographed statement from the church's top administrative body, also headed by Wilson, which asserted that the plan for formation of black unions "flies in the face of both the goals of the Seventh-day Adventist Church and our nation. It further segregates, rather than integrates, the black members of the church."

Following the vote, black leaders held a private, closed-door session to discuss further strategy. One person who was present at the meeting stressed that there was "no sentiment for a pull-out" from the church at that session.

The Seventh-day Adventist Church worldwide has a membership of about 3 million. It is theologically conservative, keeps Saturday rather than Sunday as the sabbath, and anticipates the imminent second coming of Christ.

Faithful church members follow a vegetarian diet, give at least 10 percent of their income to the church and where possible, send their children to church-controlled schools instead of public ones.

Two days after the debate on black unions, Elder Robert H. Pierson, 67, president of the worldwide church, unexpectedly announced plans to retire next January because of "health reasons." Pierson's term would not have expired until 1980,

Wilson, who has headed the North American division for 12 years, was elected to succeed him.