Embattled Prince George's County NAACP president William R. Martin charged last night that the attorney for the county school board "duped" him into negotiating an agreement to curtail the busing of county school children who live in integrated neighborhoods.

The agreement, announced Tuesday by Martin and school board chairman Norman H. Saunders, set off a storm of protest from both county and national NAACP leaders.

Although Martin continued to defend the over-all content of the agreement, for the first time last night he also expressed reservations about parts of it dealing with busing routes. In addition, he said he feared that if the agreement is fully implemented, some county schools would become all black.

Martin said he initialed the agreement during a meeting with Saunders and school board attorney Paul Nussbaum because he hoped it would provide the basis for improving busing patterns in the county, and also because he hoped it would make the national NAACP chapter more aware "of weaknesses in the local (NAACP) branch."

Martin, who made his remarks to reporters during and after the taping of the Channel 4 News Center Forum program, said he had not spoken out before because he was waiting to talk to national NAACP officials.

Announcement of the agreement followed a meeting Feb. 23 at which Martin said he expected to "just talk" with Saunders in hopes of resolving a busing complaint filed by a black county resident.

Martin said he found Nussbaum at the meeting as well. The attorney "had a pile of papers," Martin said, among them a proposal for a busing agreement.

According to Martin, Nussbaum said, "Forgive me for not telling you I had this document. I want you to agree to discuss it in secrecy with us."

Martin said Nussbuam "duped me into negotiations in that he did not say we were negotiating anything."

Rather than leaving the meeting, Martin said he realized "a game was being played" and stayed for six hours "editing" the document because he said he felt something constructive could come of it.

Neither Nussbaum nor Saunders could be reached for comment last night.

Martin said he purposely ignored a directive by the executive board of the county NAACP to consult an attorney before talking with the school board, "because I felt they were wrong."

"I made one fatal mistake when they told me to consult an attorney. I should have fought it, but I accepted it. I said [to myself] I was not going to obey the directive and I was going to get around it."

Martin said he went against the executive board because he felt there were "personalities" on the board that were destructive to its mission. "I felt if we could get the national chapter in on it, we could not only reduce busing in the county but resolve some of the problems with the local chapter."

Martin said that the national NAACP had long overlooked "personality problems" that divide the county chapter, and that he hoped to use the busing agreement as an issue that would focus national NAACP attention on Prince George's.

He declined to elaborate on problems within the county chapter.

Martin said he initialed what he termed a "proposal" for an agreement that he intended to bring back to his executive committee for them to approve.

Members of the executive committee, however, said he had no authority to draft the proposal in the first place.

Martin now says that he thought he had "edited" the proposal to a point that he himself could agree with its basic elements.

"I didn't want to bring the executive committee something I couldn't live with."

Martin said he is now "annoyed" because he was placed in a situation where he had to negotiate "a document that a lawyer should have read," he said.

Wednesday, national chairman Benjamin L. Hooks declared that Martin violated NAACP policy by not consulting with members of the national chapter before acting. And earlier yesterday 12 members of the county's 16-member executive committee filed a complaint with national NAACP headquarters in New York calling for Martin's ouster.

The agreement would allow children in integrated neighborhoods to attend neighborhood schools. Since 1973, when court-ordered busing began in Prince George's, the Naacp/ has consistently opposed any changes in the busing plan.

But Martin declared earlier this week that in the last six years growing numbers of blacks have moved into previously all white communities, resulting in busing routes that produce little integration

The agreement would require the approval of the school board and the full county NAACP chapter before it is adopted.

John Rosser, spokesman for the 12 compaining members of the county NAACP board, declined yesterday to disclose details of that complaint.