The Episcopal Church's agonizing decision to open its all-mate priesthood to women becomes effective today and within the next couple of months, more than 40 women will receive holy orders.

The vote of the national church last September to approve women priests was due in part to the efforts and politicking - ecclesiastical style - of a 29-year-old Alexandria woman, the Rev. Pat Park, who will herself be ordained Sunday.

For the past two years, Park has been cochairperson of the National Coalition for Women's Ordination, an unofficial organization within the Episcopal Church devoted to persuading delegates to last September's General Convention of the church to vote formal approval of women priests.

In addition to the traveling, speaking, caucusing, and lobbying involved in that task, she has served as deacon at Immanuel Church-on-the-Hill in Alexandria, where President Gerald Ford and his family have been members for nearly 20 years.

She was deacon-in-charge in August, 1974, and scheduled to preach the first Sunday after Ford had become president. But when Immanuel's rector, the Rev. William L. Dols heard the news, he broke off his vacation and displaced Park as preacher at the first service the Fords attended at Immanuel after he became President, she said.

"We had a little discussion about that," Park recalls now with a laugh. But Park and Dols have resolved any differences. He, along with Park's husband, Stephen, who is also an Episcopal priest, will be her sponsors at tomorrow's rite.

Pat Park had a small role in the irregular ordination of 11 women to the Episcopal priesthood in Philadelphia two years ago. "I had only been a deacon two month so I wasn't eligible to be ordained then, but I have been very supportive of them (the Philadelphia 11)," she said. Candidates for the Episcopal priesthood normally serve six months in the diaconate before priestly ordination.

The status of the women ordained in Philadelphia as well as four more ordained in a similarly unauthorized rite in Washington a year later still has not been clarified by the church. Nevertheless, two of them, the Rev. Alison Cheek and the Rev. Lee McGee, are scheduled to administer communion following Park's ordination tomorrow.

For the time being, Park will continue to serve three days a week at Immanuel Church. But she will have to commute from Richmond where she is moving with her husband and their 3-year-old daughter, Laura.

Stephen Park, who has been an assistant priest at Holy Comforter Church in Vienna, is studying pastoral counseling at the Medical College of Richmond.

Employment possibilities for a Episcopal clergy couple are tenuous, she says.

"You have to be incredibly open to any possibilities," she said. She is opposed to the two of them sharing parish duties, at least for the time being.

"I think we're too young to have a parish," she said. For that, she added, "you have to have experience; you have to have the knowledge of your strong points; you have to have age and maturity. We just don't have that."

Park will not be the first woman in the country ordained under the interpretation of Episcopal Church canon law authorizing women priests, which goes into effect today. That honor goes to the Rev. Jacqueline Means, 40, an Indiana prison chaplain who is scheduled to be ordained at 2 o'clock this afternoon at All Saints Church in Indianapolis.

On Jan. 8, another Virginia woman, the Rev. Blanche M. Powell, will be ordained in Manassas. The same day, an ordination service at Washington Cathedral will include three women; the Rev. Elizabeth Wiesner, the Rev. Carol Ann Crumley and the Rev. Pauli Murray.

From today onward, these and other qualified women will receive their priestly ordination with the formal blessing of the Episcopal Church. But there remain some sections of the church that will refuse to recognize them.

Pockets of resolute opposition to ordaining women persist, in spite of the General Convention's official action.

In November, a coalition of 17 groups and independent and unofficial Episcopal Church publications calling themselves the Fellowship of Concerned Churchmen, met in Nashville and urged formation of a separate church where ordination of women priests would not be allowed.

Last month another group, this one called the Coalition for the Apostolic Ministry, meeting in Chicago, counselso against schism, but vowed to work within the Episcopal Church to roll back the authorization to ordain women priests.

Last September The General Convention itself approved a "conscience clause" that excuses individual bishops who oppose women priests from ordaining them or placing them in parish positions if they are ordained by another bishop.

Still other opponents of ordaining women advocate the creation in the Episcopal Church of a nongeographical diocese, based solely on exclusion of women from the priesthood, where worshippers would be assured they would never have to receive communion from the hands of a woman.

A Detroit parish - Mariner's Episcopal Church - has agreed to withhold contributions to the diocesan budget and will not permit bishops to visit the parish as a protest against women priest. And St. Mary's Church in Denver has voted to withdraw from the denomination for the same reason.

No one knows how strong this kind of opposition is in the Episcopal Church or how seriously to take the threats of schism.

But one thing is certain: the church's long battle over women priests is not yet over.