The Alexandria chapter of the NAACP yesterday sued that city's school system, charging that it has systematically discriminated against blacks by losing schools in predominantly black neighborhoods.

The suit, filed in U.S. District Court by the same Richmond law firm that figured prominently in Virginia civil rights legal fights of the 1960s, seeks to reopen two elementary schools in heavily black neighborhoods.

One of the schools, Robert E. Lee, near the intersection of the Beltway and Route 1, was ordered closed last March because of declining enrollment; the other, Cora Kelly, located in the Four Mile Run flood plain, was shut down because of chronic flooding, school officials said.

The suit, prepared by veteran civil rights attorney S.W. Tucker of Hill, Tucker and Marsh, charges that the operation of public schools soley in white communities generates "feelings of inferiority" in black children.

"The removal of public institutions from predominently black residential areas will . . . stamp with official design and approval the ghetto-like quality and characteristics of such areas - making unlikely their color-blind and indiscriminate resettlement," the suit said.

School board officials had not seen a copy of the suit yesterday afternoon. But school system spokesman Dennis Leone said the system has been in compliance with federal racial guidelines since school desegregation was begun in Alexandria's secondary schools in 1971 and in elementary schools in 1973.

"We've got to close schools and it's going to be hard to close schools that don't have a black majority or a near black majority because there are more black kids in the city," Leone said.

The number of black students in the city school system dropped this year for the first time in more than a decade, but the system overall is 47 percent black, 45 percent white and 8 per cent Asian and Hispanic.

Leone also said that the racial make-up of the city is changing. "It's hard to tell what is a predominatly black area."

Leone said that four schools have been closed since 1969, a period that has seen a 29 percent drop in total enrollment. Three of the schools were in predominantly black areas. The fourth was in an area that served blacks in a public housing project and wealthy whites, Leone said.

Two new schools have opened since 1969 - James K. Polk in a heavily white area and Jefferson-Houston in a predominantly black area. There are a total of 14 elementary schools in the city.

According to the NAACP suit, Jefferson-Houston is the only elementary school now serving a predominantly black area, although Leone said that at least two other schools are in predominantly black areas and another is half and half.

In 1973, the school system adopted a desegregation plan that paired predominantly black elementary schools with predominantly white schools by busing.