Montgomery County schools "fall significantly short" of providing a quality education for black students, who year after year score lower than other groups on standardized tests and are more often suspended from school, a biracial citizen committee charged in a report yesterday.

The 70-page report, which also said blacks are routinely "herded" into special education classes without justification, was prepared by the Citizens' Minority Relations Monitoring Committee, an independent group of school parents who monitor minority issues.

At a news conference in Rockville, committee Chairman James L. Robinson said the school system deserved only a "C minus" for its efforts to address the "serious problems" facing black students in county schools.

"Problems and attitudes linger from a time when the school system was still segregated," he said. "I'm not saying there are vicious, mean racists in the school system, but there are institutional ways of doing things that still linger."

Among the report's findings:

*Black and Hispanic students perform poorly on virtually all standardized tests administered by the school system. On California Achievement Tests, for example, black student scores in math have increased slightly over the past three years, but lag behind those of white students by at least 15 points. The trend is the same in the CAT test for reading.

Black students are "grossly overrepresented" in special education categories where placement is determined by "judgmental factors." For example, blacks constitute 25.8 percent of the students deemed "emotionally impaired," even though they make up only 14.5 percent of the school enrollment.

*Minorities comprise 28 percent of the school enrollment, but only 11.8 percent of the school's professional staff, a figure virtually unchanged from five years ago. Most school principal positions are still held by white males.

*Although school suspensions are declining, blacks still are suspended at nearly three times the rate of whites. The report recommends placing the authority for suspensions in the hands of independent hearing officers.

Reaction to the report, the fourth released by the committee since 1981, was mixed among school officials.

"It doesn't make any contribution to the resolution of this problem to issue a report in that tone annually, as though no one were paying any attention," said Board of Education President Robert E. Shoenberg.

School Superintendent Wilmer S. Cody said in a prepared statement that the issues cited in the report already have been identified for "increased attention" by the school system.

Two years ago, the school board ordered Cody to develop a special program to increase minority performance in the classroom and minority participation in higher level academic courses.

The program was implemented during the 1984-85 school year and has already produced modest gains, according to Cody.

"It's a matter of degree as to what Robinson said we are, or are not, doing," said school spokesman William Henry. "We are making progress. What he is saying is, it needs to be done faster."

The committee's charges come at a time when increasing attention is being focused on the performance of black students in area school systems.

In Alexandria, standardized test results released this week showed black student scores lagging significantly behind those of white students, while in Prince George's County, School Superintendent John A. Murphy announced in July a program to battle a similar disparity in test scores.

Robinson said the committee will request a meeting with the school board to discuss the findings.