The superintendent of the Prince George's County public schools defended the school system yesterday against accusations of racial discrimination and charged that the NAACP's effort to reopen a 1972 desegregation case was politically motivated.

"The claims of discrimination lodged against this school system are unfounded," said Superintendent Edward J. Feeney. "They appear to be attempts to develop a legal and political argument based on numbers, not people and education standards.

"We do not classify students by race, we do not assign students to classes because of their race, we do not suspend students by race, we do not identify whole groups of students by race and treat them differently than other students," the superintendent said.

Feeney's comments came in response to a motion the NAACP filed Tuesday in U.S. District Court in Baltimore. The civil rights group charged that despite nine years of federal court-ordered busing, the county schools are becoming increasingly segregated and asked the court to reopen the case and remedy the situation.

The case was closed officially in 1975 but Judge Frank Kaufman, who heard the case, agreed to allow it to be reopened at any point if either side had new evidence to present.

The NAACP's action, which had been threatened for at least a year, was sharply criticized by school board members and others associated with the school system.

"I'm terribly upset by all this," said board member A. James Golato, reflecting the sentiments of most of the nine-member board. "We've been hypercautious about not doing anything that could lead to resegregation. The NAACP has became a bunch of masochists."

Other board members said they thought the civil rights group was simply reopening the suit in an effort to show a willingness to counter the conservative trend of the Reagan administration.

"There are a number of ramifications to being a suburban school district in the nation's capital," said school spokesman Brian Porter.

From other political quarters, however, the response was more muted, tinged with fears that a new court case would lead to the same sort of turmoil touched off in the county in 1972, when the desegregation suit was filed by a group of black parents.

"People who remember 1973 when court-ordered busing began are very concerned," said Prince George's Del. Timothy F. Maloney. "It was such turmoil, the county was turned upside down. It was necessary but it was so difficult on the county that it's never been the same since."

Concern was voiced as well from some unexpected quarters. Sylvester Vaughns, one of the original plaintiffs in 1972, said he did not approve of the NAACP action. "I think there is a difference between now and 1972," Vaughns said. "In 1972, I went into schools and there were differences between the blacks ones and the white ones . I think we should just leave it alone. Things have settled down."

Vaughns' remarks reflect the increasing disagreement among blacks over the effectiveness of busing. Some parents from middle-class communities have said they would prefer to curtail busing and send their children to neighborhood schools, a position opposed by the NAACP as well as most black politicians in the county.

Critics of court-ordered busing have blamed it for the departure of some businesses and thousands of affluent white families from the county. Since 1972 Prince George's has seen a huge change in its population as large numbers of white families left the county and equally large numbers of blacks moved in. The county is now nearly 40 percent black, though most of its elected representatives are white.

The demographic changes have been most apparent in the public schools, where the proportion of black students has jumped from nearly 20 percent in 1972 to 50 percent today. Because busing patterns have not changed since the suit nine years ago, many schools are no longer integrated in the way the court intended. Some schools now are close to 90 percent black.

While the NAACP believes that the school board should have acted to ensure that the schools stayed racially balanced, board members have long maintained that the changes that have resegregated some schools were the product of housing pattern shifts that were beyond the board's control.

Feeney acknowledged that the shifting populations have made it difficult to maintain racial balance at every school, but said the school administration has ensured that all students are treated equally regardless of race.

NAACP General Counsel Thomas Atkins said yesterday that he will wait until Judge Kaufman sets a court date to debate the charges. He also disputed Feeney's claim that politics had played a role in the request to reopen the suit. "We're not trying to make a statement," he said. "This is just another school district where the administration is taking actions to segregate the schools."