Morton L. Solomon, 49, a supervising accountant with the Government Accounting Office and a resident of the Washington area since 1956, died Sunday in an boating accident on Lake Caroline near Ladysmith, Va. He lived in Rockville.

The Caroline County sheriff's office said that Mr. Solomon, who was accompanied by his wife, drowned after the boat they were using accidentally capsized. Mrs. Solomon was able to swim to shore.

Mr. Solomon, who was born in Scranton, Pa., earned a bachelor's degree in business administration at Pennsylvania State University. He then went into the Army and served in Germany and with the Army Security Agency.

He settled in the Washington area in 1956 and joined the GAO in the same year. He was a supervising accountant at the time of his death.

Mr. Solomon was a member of the National Association of Certified Public Accountants and of Temple Sinai in Washington.

Survivors include his wife, Marlene G., of Rockville; three daughters, Susan Solomon Turner of Vienna, Diana Solomon of Minneapolis and Wendy Solomon of Rockville; his father, Max Solomon of Scranton, and one sister, Natalie Mandel, also of Scanton.

The family suggests that expressions of sympathy be in the form of contributions to Temple Sinai in Washington.