Members of the Newspaper Guild at the Washington Post overwhelmingly approved yesterday a three-year contract that provides increased pay for editorial and commercial workers and rescues the union's pension and health benefit programs from financial difficulty.

In an action touched with symbolism, the voice vote on the contract by about 200 Guild members was held at the Metropolitan AME Church on M Street NW, around the corner from The Post. The church was the site of excited and often angry Guild meetings during a 1975 Post Pressmen's strike which left the Guild divided over whether to support the pressmen.

In contrast to those heated times, the meeting yesterday was calm and brief. The vote was nearly unanimous. Only one person said "nay."

The new Guild contract provides pay increases totaling up to $82 per week over the next three years, plus provisions for cost-of-living increases of at most 6 percent in the second and third years. The raises are retroactive to April 1.

In addition, the company has agreed, if legally possible, to take over the Guild unit's health and pension funds in order to buttress employe benefits that have been in financial jeopardy. And for the first time under any Newspaper Guild contract in the country, part-time employes will be able to buy into the health insurance plan at half rate. Part-time employes make up about one fifth of The Post's work force.

To reach a compromise, the Guild negotiating team yielded on the issue of union security, surrendering what had been a requirement eight of 10 new hires join the Guild. Since 1976, however, that requirement had been abandoned at the paper.

The guild and the company also agreed to abide by eventual National Labor Relations Board rulings on the membership eligibility of about 160 mid-level editorial staffers. And the union backed off from an effort to force the upgrading of some jobs.

For its part, the company agreed to withdraw a demand for a no-strike clause in the new contract.

A prevailing mood among Guild members was relief at having reached an agreement after more than three years of on-again, off-again talks between The Post and the Washington-Baltimore Newspaper Guild.

"I'm delighted, I'm glad it's over, and I'm glad we have a contract," said Charles Babcock, co-chair of the Post unit.

Post management expressed the same sentiment. "We are both relieved and pleased that the long, arduous ordeal of negotiating a new labor agreement with the Guild has come to a successful conclusion," Lawrence Wallace, the paper's vice president for labor relations, said in a statement. He added that the new contract "will stabilize our relations with the Guild and the employes it represents."

Then looking ahead to difficult negotiations with several other Post unions this year, Wallace said, "With the Guild contract out of the way, we certainly hope we can now make contract settlements with the other unions with whom we are negotiating."

Those other unions represent the paper's machinists, typographers, printers, electricians and mail room employes.

Other significant features of the new contract include a phased retirement plan, a revised grievance procedure, and changes in sick leave provisions.

The Newspaper Guild represents editorial, clerical and commerical employes. About 550 of the approximately 1,100 Post workers covered in these groups are dues-paying members of the union.

Negotiations between the union and the company had been unproductive since expiration of the old contract in March 1976. Serious progress in the talks began in the spring.