A U.S. District judge yesterday ordered the federal Drug Enforcement Administration to pay about $2 million in back salary to more than 200 black special agents who he found had been the victims of race discrimination within the agency since 1972.

Judge Aubrey E. Robinson Jr. also ordered the DEA to promote one black agent for every two white agents promoted into the top six grade levels until the number of black agents at each level reaches 10 percent of the total number of agents at those levels. The DEA will have a maximum of five years to bring the number of black agents up to the 10 percent level, Robinson said.

"Under this plan, black agents will be employed in the positions they should have occupied absent the unlawful discrimination," Robinson said in an opinion issued Wednesday. The salary level ranges from $33,586 at the GS-13 level to $57,500, which is the federal pay cap. In 1981, blacks held 4.2 percent of the special agent jobs at DEA at grades from GS-13 through GS-18.

Government attorneys said that it had not been decided whether to appeal Robinson's decision.

While the DEA is meeting the promotion goals, Robinson said, the agency will have to pay "frontpay" to black agents who continue to experience "economic harm" while the agency is remedying discrimination in promotions. Frontpay is intended to compensate black agents until the judge's promotion order is complied with.

William T. Lake, an attorney for the black special agents, said that about 100 black agents at the GS-12 level and above would be eligible for frontpay.

Lake said that recent figures show that blacks make up about 8 percent of the DEA's special agent force. The black agents argued that they were clustered in low grade levels, from GS-7 through GS-12, and that their chances of promotion diminished significantly in the upper grade levels. In his order, Robinson noted that statistics show that black agents make up at least 10 percent of agents at each level up to GS-12.

Robinson had ruled a year ago that the DEA had violated Title VII of the Civil Rights Act of 1964 in discriminating against blacks in a variety of areas, including work assignments, discipline and promotions, and had allowed "gross disparities" to exist in salary levels.

As part of his order this week, Robinson required that a monitoring committee of black special agents be set up to ensure that DEA complied with his ruling. In addition, Robinson said that Lake and other lawyers from the Washington firm of Wilmer, Cutler & Pickering, who represented the black special agents at no charge, are entitled to attorneys' fees and costs.