The nation's Roman Catholic bishops ploughed through a formidable list of issues at their week-long annual meeting here that ended yesterday with an equal number of ecclesiastical matters and worldly concerns.

The nearly 300 prelates took steps aimed at reversing the effects of two Supreme Court decisions: the 1973 action legalizing abortion and the decision earlier this year eliminating aid to educationally disadvantaged children in parochial schools.

They adopted with little debate a detailed plan for antiabortion activities that calls on Catholics to join forces with other forces to form political action groups in every congressional district in the nation.

The 7,000-word statement differs from earlier antiabortion plans in that it places its fight against abortion alongside opposition to "nuclear war, capital punishment, degrading poverty, or racism and other forms of discrimination" as part of the church's "consistent ethic of life."

But the statement said that "among the many important issues involving the dignity of human life with which the church is concerned, abortion necessarily plays a central role."

The statement, which denounced the use of violence in opposing abortion, outlined a wide range of educational and pastoral approaches, including "efforts to promote the virtue of chastity and enable young men and women to take responsibility for their power to generate human life."

In another statement, the bishops branded as "unjust, discriminatory and narrow" the Supreme Court's July 1 decision, which put an end to federally funded remedial programs for educationally disadvantaged children where such programs were conducted in parochial schools.

Discussion of the court's controversial 5-to-4 decision unleashed bitterness and anger among the bishops. "It is blatant discrimination, blatant injustice," said Cardinal John Krol of Philadelphia. Krol argued that the 20-year-old program did not violate First Amendment prohibitions against church-state entanglement since it involved "aid to the child and not to the institution."

Noting the bishops' long track record of protesting injustice in other parts of the world, Archbishop Edmund C. Szoka of Detroit said, "We ought to say this decision is wrong, this is discriminatory and we ought to protest it."

Archbishop Peter Gerety of Newark proposed that the bishops produce a pastoral letter on church-state relations in observance of the 1987 bicentennial of the Constitutional Convention of the United States. The bishops could "clarify the Catholic understanding" of church-state issues involved in the First Amendment "in such a way that the national discussion will be enhanced," Gerrity said.

The bishops asked their committee on social development to study the feasibility of Gerrity's proposal, in light of their commitment to produce two other pastorals -- one on women and one on the economy.

The bishops were generally enthusiastic over the second draft of their projected pastoral letter on the economy, which is to be submitted for final approval at their meeting a year from now.

The document has been criticized by conservatives in and out of the church for its demand for the elimination of poverty as "an imperative of the highest priority" and its stress on "economic rights" -- the right of food, clothing, shelter and medical care -- on a par with human rights.

But Archbishop James A. Hickey of Washington echoed the sentiments of many in praising the document. He urged that the drafting committee "in no way compromise on economic rights, as some would wish. That's not some new concept. It's a part of our teaching on human rights."

In a prelude to the summit conference, the bishops drafted a brief letter to President Reagan, pledging "best wishes and prayers" for "a lessening of tensions between the superpowers and negotiated deep cuts in the military weapons and forces of our countries."

The bishops heard a report from Krol, who headed a special committee to investigate charges made last summer that Catholic Relief Services mishandled funds donated for famine relief in Africa.

Krol said that CRS, which raised nearly $50 million for that cause, "is using its donations wisely and well in Ethiopia," providing the "maximum assistance possible for the people who are starving."

He said that in some situations the agency collected "voluntary token contributions" -- the equivalent of 25 cents for $40 worth of food -- from recipients. The practice, he said, helped the needy "maintain some dignity and not regard themselves as beggars.

"There is absolutely no evidence whatsover that anyone . . . was ever denied access to food because of inability to pay," Krol said.

Another message to the president, dealing with the crisis on American farms, urged both government support and "effective methods of managing the food supply" to prevent a bad situation in American agriculture from worsening.