The Pennsylvania Supreme Court yesterday ordered a new trial for former United Mine Workers President W.A. (Tony) Boyle, convicted in 1974 of murder in the 1969 deaths of UMW insurgent Joseph A. (Jock) Yablonski, Yablonski's wife and daughter.

The justices ruled 6 to 61 that the trial court erred in not letting Boyle put on the stand a witness he claimed would aid his cause. Boyle said the witness' testimony would help show that others involved in the case had an independent motive for murdering Yablonski.

He was accused of having ordered these others to kill Yablonski. He denied the charge, claiming the others acted on their own.

Boyle, now 74, has been serving a sentence of life imprisonment in Western Penitentiary at Pittsburgh. Doctors say he has a heart problem that has been causing him chest paisn, and he has been in a four-bed hospital ward in the prison for some time.

Deputy prison Supt. Charles Zimmerman said Boyle was "calm, but obviously pleased," when told yesterday of the court's decision. "He just accepted the news calmly," Zimmerman said, adding that Boyle had said he would make no public statement.

Burton A. Rose, one of Boyle's attorneys, said in Philadelphia a motion would now be made next week in Media, Pa., where Boyle was tried, to have him freed on bail. Another Boyle attorney. A Charles Peruto, said the retrial will probably take place in Media, and must begin within 120 days.

Boyle was the final one of nine persons to be convicted in the Yablonski murders. The other eight were three gunmen who did the actual shooting; tow go-betweens, one of them the wife of one of the gunmen and the other the wife's father; and three high-ranking officials of the mine union's District 19, an administrative area in eastern Tennessee and Kentucky.

Boyle, while under challenge from Yablonski for the presidency of the union in 1969, was said to have gone to the District 19 officials to arrange the murder, and they in turn were said to have hired the gunmen through the go-betweens.

The successful special prosecutor in all nine Yablonski trails was Richard A. Sprague, then first assistant district attorney in Philadelphia and now chief counsel to the House committee that is seeking funds to investigate the assassinations of President John F. Kennedy and Martin Luther King Jr.

Sprague was out of town yesterday and could not be reached for comment on the case. One question, however, is whether he will seek to play any role in the Boyle retrial. If he does, that could further complicate the affairs of the Kennedy-King assassination inquiry committee, which has become controversial and which some members of Congress would like just to fade away.

Members of the Yablonski family also declined to comment yesterday.

The current UMW president, Arnold Miller, would say only that he was "surprised, very surprised" by the new court order, while union secretary-treasurer Harry Patrick expressed the fear it might further divide the union.

Yablonski, who had once been a Boyle lieutenant, ran against Boyle for the presidency in 1969 and lost. He was killed in his Clarksville, Pa., home three weeks later, in the early morning of Dec. 31. The next year, a federal judge found there had been assorted irregularities in the first election and ordered a second one held under federal government supervision. Miller was nominated by the insurgents to run against Boyle in Yablonsik's place, and he won.

The witness Boyle wanted to put on the stand at his trial is a federal auditor. Thomas Kane, who had found some suspicious items in the books of District 19. Boyle's contention was that the District 19 officials feared what Yablonski might do if he were elected union president and found out about these items. But Sprague successfully objected at the trial, and Kane was never allowed to testify.

The court said yesterday he should have been, and in the new trial Boyle will presumably have the right to make his case in full.