Maryland prison officials yesterday failed to meet the first deadline in a court-ordered schedule to relieve overcrowding in two Maryland prisons.

The state has appealed the two U.S. District Court rulings that set up the deadlines for removal of inmates, but yesterday, as the first deadline passed, the appeals court had not yet issued its ruling.

States Attorney General Francis (Bill) Burch previously has said that meeting the deadlines would pose "a substantial threat to public safety."

The lower court rulings, issued last August, ordered the state to remove 1,000 inmates by April 1, 1979, from the overcrowded Maryland Penitentiary in Baltimore and Maryland House of Correction in Jessup. The court-imposed schedule required the removal of 100 inmates from each of the institutions by Dec. 1.

In a report to the court yesterday, officials said they had reduced the population at the maximum-security penitentiary by 69 inmates and at the medium-security House of Correction by 49, according to Assistant Attorney General Stephen B. Caplis.

The judges, in separate opinions last May, ruled that the two prisons were so overcrowded that conditions represented cruel and unusual punishment for inmates and therefore were unconstitutional.

The state has asked the courts to give it until June 1, 1980 to relieve the overcrowding. By then, officials estimate, a 500-bed addition to the House of Correction will be completed.

In its report yesterday, the state said it had complied with two other portions of the order affecting the use of a special confinement area in the Jessup institution and an isolation area in the penitentiary, Caplis said.