Former White House aide Charles W. Colson's new vocation - preaching Christianity in prisons - persuaded the D.C. Bar's disciplinary board that Colson should not be disbarred for his Watergate-related crime.

Instead, the bar's disciplinary board by a 4-to-3 vote recommended a five-year suspension from the practice of law for Colson, who pleaded guilty and served seven months in prison for obstructing justice by trying to influence Daniel Ellsberg's Pentagon papers trial.

The final decision on disciplining Colson is up to the D.C. Court of Appeals.

Colson already has been disbarred in Virginia and banned from practicing law in the U.S. District Court here, which runs its own disciplinary procedures. But the D.C. Bar board followed the Supreme Court of Massachusetts, which suspended Colson indefinitely but allowed him to apply for reinstatement in 1979.

Egi Krough, another Nixon White House aide, was disbarred recently by the Washington State Supreme Court after he pleaded guilty to a similar Watergate-related charge - conspiring against a citizen's rights in connection with the burglary of the office of Ellsberg's psychiatrist.

Colson's new Christian vocation clearly persuaded a slim majority of the D.C. disciplinary board not to disbar him.

"The board," the majority wrote, "believes that respondent Colson is aware of the serious implications of his violations of law and professional ethics. His work on behalf of prisoners demonstrates a real effort to rehabilitate himself. In this regard Mr. Colson distinguishes himself from many attorneys whom this board has disciplined and who have failed fully to realize the implications of their conduct . . ."

To recommend disbarment, the board continued, would be a rejection of the mitigating factors.

A three-member minority of the board said Colson should be disbarred because "the seriousness of his misconduct" warrants nothing less "than the most unequivical expression of disapproval . . ."

The facts that the voluntarily pleaded guilty, cooperated with the prosecutors, was a "model" prisoner and has moved fully into preaching Christianity in prisons - "if they continue" - could be used as reasons for reinstating Colson as a lawyer at the end of five years even if he were disbarred, the minority on the disciplinary board wrote.

A Bar Association Hearing Committee, which listened to evidence in the case, recommended to the disciplinary board that Colson be disbarred.

But the board recommended a five-year suspension retroactive to June 23, 1974, the date Colson was suspended under court rules for being convicted of a serious crime but before the official disciplinary process began.

If Colson had been disbarred, he would have been eligible to apply for reinstatement in June, 1979.

All members of the disciplinary board are attorneys. Voting to suspend Colson were Wiley A. Branton, David T. Austern, Goley Teal Butcher and Lawrence J. Latto. Voting to disbar him were Daniel M. Gribbon, the board's chairman, Harry Huge and Marna S. Tucker.