Boston — America's Roman Catholic bishops have initiated an intensive discussion among members of their faith on the shape of the United States economy. In a draft pastoral letter, a committee of five bishops, headed by Archbishop Rembert G. Weakland of Milwaukee, take a strongly liberal position on such issues as unemployment, poverty, welfare reform, cooperative ownership and worker participation in corporations, and aid to developing countries.
Anticipating the mostly left-of-center views of the draft letter, a group of conservative lay Catholics issued their own study, entitled ''Toward the Future; Catholic Social Thought and the US Economy,'' last Tuesday. Like the bishops' draft letter, it is intended to apply Catholic moral and ethical teachings to the nation's economic system.
The releases of the bishops' letter and lay Catholics' report were timed to fall after the election, in order to avoid charges of partisanship. Nonetheless, the bishops' recommendations are so often contrary to those of the Reagan administration that the pastoral letter is bound to be highly controversial in Washington, as well as throughout the Catholic community.
Last year the National Conference of Catholic Bishops approved a letter on ''The Challenge of Peace: God's Promise and Our Response,'' which included advocacy of a nuclear freeze. It prompted a major debate that extended beyond Catholic circles. The Reagan administration sought to alter some of the language in the original draft.
This new document, entitled ''Pastoral Letter on Catholic Social Teaching and the US Economy,'' could prompt even more controversy.
One reason is its content. For example, in looking at unemployment, the draft letter calls for a major new policy commitment to achieve full employment, which the bishops define as a 3 or 4 percent unemployment rate. Most economists would say such a low jobless rate would prompt much higher inflation.
It also calls for expanded government programs for direct job creation for the ''structurally unemployed.'' These programs could provide public-service employment or public subsidies for jobs in the private sector.
In dealing with poverty, the bishops advocate reforms that ''eliminate or offset the payment of taxes by the poor.'' While not mentioning the Reagan tax cuts directly, they note that ''in recent years the total amount of taxes has increased substantially for the poor, while those at the top of the income scale have received significant reductions.''
The five bishops also maintain that the current level of federal and state subsidies for day care of children is inadequate.
Talking of welfare, they imply that current welfare levels are inadequate to provide recipients with ''decent support.'' Even combined with food stamps, welfare typically amounts to less than three-fourths of the official poverty level, they note. The bishops further urge that the federal government establish national eligibility standards and a national minimum benefit level for public assistance programs.
In contrast, the lay report, although not specific in recommendations, refers to the ''principle of subsidiarity'' - the view that ''social decisions ought to be taken by the community closest to the relevant concrete realities.'' Many conservatives, in other words, would prefer the states deal with such matters as welfare.
Looking at plant relocations, the bishops comment: ''The capital at the disposal of management represents to a significant degree the investment of the labor of those who have toiled in the company over the years, including currently employed workers. It is patently unjust to deny these workers any role in the shaping of the outcome of such difficult choices.''
In other areas regarding relations between workers and managers, the bishops take positions that are sympathetic to a greater role for workers in management decisionmaking and corporate ownership.
Reviewing the US position in regard to the developing countries, the draft letter recommends that the nation ''give serious consideration to some forgiveness'' of the massive debts owed the US by the poor nations. It also urges the US to boost its contribution to the International Development Association to a level allowing the ''soft loan'' affiliate of the World Bank to make loans of at least $12 billion over the next three years - a level sought by most industrial nations. The Reagan administration insisted on keeping its contribution to a level that held the amount to $9 billion.
It calls for an international agreement to reduce arms sales to third-world countries. It urges the US to support UN efforts to develop a code of conduct for foreign private investment.
In general, the draft letter is not anticapitalistic; but it is far more critical and reform-minded than are many conservative Catholics. Both the bishops and their critics see the problems; their remedies, however, differ.
Aside from content, the bishops' pastoral letters are debated heatedly because Catholics regard such documents as highly important. The Catholic church claims 52 million members and manages a school system, from kindergarten to university levels, with about 3.5 million students. The pastoral letters are used for discussion and teaching in church study groups, schools, and seminaries. Thus they are considered likely to have a major influence on the views of present and future generations of Catholics.
This first draft of the new letter will be presented to more than 300 bishops at a national meeting in Washington that began Monday and lasts through Thursday. It will undergo two major revisions before being finally voted on in November 1985.