Rep. Frederick W. Richmond (D-N.Y.) pleded innocent yesterday in D.C. Superior Court to one count of sexual solicitation and was immediately enrolled in a first offender treatment program.

Richmond, 54, was charged yesterday in connection with an incident February at his Northwest Washinton home involving a male undercover police officer. Richmond, in a statement issued by his lawyers Wednesday night, acknowledged that he had solicited the officer "with payment of money."

The two-term congressman also said in the statement that he "made that he "made solicitations with payment of money to ayoung man beginning almost a year ago . . ." Richmond was charged only in connection with solicition of the police officer.

In his statement, Richmond said he has no "logical explanation" for the incidents, and said he had sought a "appropiate professional advice." As a condition of his participation in the first offender program, Richmond has agreed to continue that treatment, the U.S. attorney's office said.

After a brief hearing in SUperior Court yesterday, Judge Dyer Justice Taylor released Richmond on his personal recognizance and scheduled a trial by a judge for May 5. The sexual solicitation charge, a misdemenaor, is punishable by 90 days in jail. a $250 fine or both.

Under terms of the first offender program, the charge against Richmond will be dismissed bt the government on the trial date or earlier, if the congressman has complied with the conditions of his participation in the program, the presecutor's office said.

James N. Ownes, chief of the misdemeanor trial section of the U.S. attorney's office, aid yesterday the enrollment in the first offender program is "standard" for all persons charged with violation of sexual solicitation laws, if the person has no prior crimnal record.

First offenders charged with shoplifting, petty larceny and possession of small amounts of marijuana - all of which are misdemeanors - also can participate in the program, Owens said.

Last year, 2,000 persons were enrolled in the first offender program. Of this total, 1,2000 participants were charged with sexual solicitation, Owens said.

Richmond, a millionaire industrialist, represents the 14th congressional district in Brooklyn. Yesterday, 20 members of the New York delegation to the House of representatives issued a written statement in which they offered their "compassion and understanting" to Richmond, whom they described as "one of the most effective and hard-working members of Congress." Richmond is secretary of the New York delegation.