The Justice Department issued a 55-page defense of its civil rights enforcement policies yesterday, saying its rejection of school busing and racial quotas is not a retreat, but a commitment to equal treatment for all.

The report is an extraordinary point-by-point rebuttal of the Leadership Conference of Civil Rights' February indictment of Reagan administration policies. That report accused the Justice Department of giving in to prejudice and political pressure and disregarding civil rights laws.

The Justice Department response called the group's report an effort "to revive support for discredited civil rights remedies and to manipulate emotions through selective citation of fact, mischaracterization and irresponsible rhetoric."

Justice Department spokesman Art Brill said the "content and tone of the leadership conference report necessitated a comprehensive reply to set the record straight and dispel misperceptions and misunderstandings."

The reply also comes just before Assistant Attorney General William Bradford Reynolds, head of the civil rights division, is scheduled to testify before the House civil and constitutional rights subcommittee tomorrow.

The unsigned report begins with a statistical recitation of what it called the civil rights division's "commendable record of accomplishment." It said there have been more criminal prosecutions of racial violence and police brutality cases than in any single year of prior administrations.

The division also has reviewed an "unprecedented" 8,400 electoral changes under the Voting Rights Act and has rejected redistricting plans for Georgia, North Carolina, Texas, Arizona, South Carolina, Virginia, Mississippi and New York City as racially discriminatory.

The report rejected the charge that its decisions have been forced by political pressure. "Plainly, the mere receipt of gratuitous advice, from whatever quarter, is a poor barometer of 'political interference,' " it said.

The leadership conference's real complaint, it said, is "with the Reagan administration's efforts to develop more realistic and responsive civil rights remedies to replace such discredited and extremely unpopular relief as mandatory busing and racial quotas."

Justice's response examined court decisions in detail to back up its claim that busing is not a required remedy in school desegregation cases and that hiring preferences for minorities are not permitted by equal employment laws. The report said the administration has sought "more effective alternate remedies," but did not spell them out beyond saying civil rights enforcement should be color-blind.

The unidentified authors also defended the department's failure to take a legal stand on various bills to strip the Supreme Court and lower courts of jurisdiction to hear politically sensitive cases on issues such as busing or school prayer.

They said the proposals "raise difficult issues" and are being given "careful consideration."

The report said it hoped the leadership conference would join it in battling racial discrimination "rather than expending further resources and energy on political sniping that neither furthers nor enlightens the debate."

William Taylor, principal author of the leadership conference report, said yesterday that his group will be glad to meet with Justice Department officials, but sticks by its conclusion that the department is not enforcing the law.

He said the department's "anonymous defense" does not identify any of its new initiatives. "The only alternatives alluded to are the old and discredited doctrines of 'freedom of choice' and 'separate but equal.' "