The U.S. Commission on Civil Rights yesterday fired off another round of reports attacking the Reagan administration's commitment to equal educational opportunity, charging that opposition to busing to achieve school desegregation amounted to tacit opposition to desegregation.

"If a school desegregation plan requires the transportation of students for effectiveness, then busing is required," one of the commission's reports said. "To speak against busing in these circumstances is to speak against school desegregation. A right without a remedy simply is illusory."

In a separate report, the commission said cutbacks in the Education Department's fiscal year 1983 programs would mean "a child's education will again become the happenstance of geographical location." It added that "severe budgetary cuts at all education levels and the absence of any guarantees for equitable participation in the new block grant approach . . . will undermine the fragile gains made by the least privileged in our society."

At the same time, chairman Clarence M. Pendleton Jr., a San Diego Urban League official appointed by President Reagan, reiterated his opposition to busing and his support for voluntary desegregation.

Both the Justice and Education departments responded to the commission yesterday with statements criticizing busing's ineffectiveness. "In city after city, we have seen the courts' preoccupation with busing drive large numbers of students from the public schools, in many instances increasing, rather than decreasing, racial isolation," said a statement issued from the office of William Bradford Reynolds, assistant attorney general in charge of the Justice Department's civil rights division.

"By combining school desegregation with educational programs of high quality, our objective is to retain parents and students in the public school systems as satisfied consumers of public education."