A federal appeals court yesterday upheld the murder convictions of former Army captain Jeffrey MacDonald in the mutilation deaths of his wife and two daughters at Fort Bragg, N.C., in 1970.

"Our canvass of the record gives ample warrant for the verdict," the 4th U.S. Circuit Court of Appeals said.

The court added there was insufficient evidence to support MacDonald's claim that drug-crazed hippies broke into his Fort Bragg home and committed the murders while chanting, "Acid is groovy. Kill the pigs."

MacDonald, 38, a former Green Beret doctor, was convicted by a U.S. District Court jury in North Carolina in August, 1979, of fatally stabbing and beating his pregnant wife, Colette, 24, and their daughters, Kimberly, 6, and Kristen, 3.

He was sentenced to three life terms in prison. In July, 1980, the 4th Circuit Court reversed the conviction on grounds MacDonald had been denied a speedy trial. The Army had investigated the crime, but never brought charges. MacDonald was indicted by a federal grand jury in 1975.

But last March 31, the U.S. Supreme Court ruled that MacDonald's rights had not been violated by the delay and reinstated the conviction.

MacDonald subsequently made a new appeal to the circuit court here on new grounds. His counsel contended the lower court judge improperly excluded testimony of witnesses who could have helped corroborate the story of a onetime police informant who claimed she witnessed the murders by a satanic cult.

The appeals court said in its unanimous opinion that the evidence showed that the informant's memory "was exceedingly poor and that she was constantly under the influence of narcotic drugs."