The Rev. Charles E. Curran of Catholic University, fighting to prevent Vatican censure, received support yesterday from graduate students at the university and from several prominent American churchmen.

Curran, 51, a leading moral theologian, disclosed Tuesday that he had been ordered by the Vatican's Sacred Congregation for the Doctrine of the Faith to retract his teachings on some aspects of sexual ethics or face losing his license to teach as a Catholic theologian.

Graduate theology students at CU began gearing up yesterday for what they said would be a nationwide campaign to send letters and petitions in Curran's behalf to the Vatican and Archbishop James A. Hickey of Washington, who is chancellor of the university.

Bishop Matthew Clark of Rochester, N.Y., Curran's ecclesiastical superior, issued an unusually strong statement in support of the liberal theologian, warning that sanctions against him would cause long-range damage to the church in this country.

National Catholic News Service reported that Cardinal Joseph L. Bernardin of Chicago, who was in Rome on other business, pressed the Congregation for the Doctrine of the Faith to reconsider a compromise it had rejected earlier.

Curran had offered to stop teaching sexual ethics at Catholic University and to accept a public statement from the Vatican of the "errors and ambiguities" in his teachings, in return for continued recognition as a Catholic theologian in good standing.

Past presidents of the Catholic Theological Society of America, which Curran himself once headed, issued a statement asserting that "very many Catholic theologians . . . do dissent" from some church teachings in the way that Curran does, and that if Curran is disciplined, others should be as well.

At a noon rally at Catholic University yesterday, former students of Curran praised him. Under Curran's tutelege, said seminarian Jack Lombardi of Baltimore, "I have not only learned the teachings of the church . . . I have also learned to think for myself."

Curran's defense at CU is led by a group called Friends of Catholic Theology in America, formed more than a year ago to encourage development of a theology that incorporates the experience of American Catholics.

In a separate but related matter, it was learned yesterday that a Vatican official will come here next week to meet with a group of nuns who are still under a doctrinal cloud for publicly questioning the Catholic church's stand on abortion during the 1984 presidential campaign.

Church leaders here declined comment on the scheduled visit of an official of the Sacred Congregation for Religious and Secular Institutes, the Vatican department that 18 months ago ordered 24 nuns who signed a controversial newspaper advertisement to recant or face expulsion from their religious orders.

Eleven of the 24 nuns are believed to have been cleared by the Vatican, although none has formally recanted.

A church official, who asked not to be identified, said the Vatican is no longer demanding that the women recant, but is concerned that they "know the church's teaching" in opposition to abortion "and adhere to it.