U.S. intelligence is examining the possibility that a Soviet brigade in Cuba may be there to demonstrate large unit tactics and field maneuvers to Cuban soldiers, a senior State Department official said yesterday.

Such a mission would seem to give some credence both to U.S. official statements that the Soviet force is a cohesive unit with combat armaments and to Soviet counter-statements that it is "a training center" with no combat role.

The U.S. official, who spoke to reporters on condition that he not be named, said this is only one of several possible missions for the Soviet brigade that are under study by U.S. intelligence. State Department officials denied that disclosure of this possibility was a "trial balloon" designed to point the way to a likely settlement of the U.S. Soviet dispute.

As Secretary of State Cyrus R. Vance and Soviet Ambassador Anatoliy F. Dobrynin met for the second time on this issue at the State Department, U.S. sources said major points of discussion have been the nature and functions of the Soviet troops in Cuba.

One possible method of resolving the dispute, which has jeopardized ratification of the strategic arms limitation treaty (SALT II) and threatens to damage relations between the superpowers, is to define clearly a non-combat role for the Soviet force. Such a settlement, if accepted by both sides, could leave the Soviet troops and most or all of their equipment in Cuba, but without the status of a "combat unit" in U.S. eyes.

Some U.S. senators, particularly those opposed to SALT II, have made it clear that they will not be satisfied with any settlement less than the verified departure of the Soviet brigade. Other senators, however, would settle for a U.S.-Soviet agreement well short of this.

President Carter and Vance have been vague in their public descriptions of the requirement for a settle- ment of the issue, saying only that "the status quo" of Soviet troops in Cuba is not acceptable. Some sources believe there is the definite possibility of a dispute within the administration over the terms if and a potential settlement comes into view.

Vance told reporters at the Capitol, following a private briefing for Sen. John Stennis (D-Miss), chairman of the Senate Armed Services Committee, that he expects to meet with the Soviet ambassador almost daily until the issue of the troops in Cuba is resolved.

Vance's remarks indicated that, despite a tough Pravda editorial Monday and Soviet polemics on the issue, American officials continue to believe there is a clear chance for a negotiated resolution. Continued Vance-Dobrynin negotiations day after day also may serve to cool down the crisis atmosphere in Washington on the politically touchy issue.

State Department spokesman Hodding Carter reiterated at a briefing for reporters that Soviet training troops have been in Cuba for some time, and this does not run counter to U.S.-Soviet agreements.

Carter would not define the "combat role" to which the U.S. objects, except to say, "I am talking about what they are functionally able to do . . .with their associated equipment."

The United States has known since 1962 that the Soviet Union has had military advisers and training troops in Cuba, and since the early 1970s that additional Soviet military personnel were on the island to operate and guard a communications intercept facility. Despite isolated bits of intelligence dating at least to early 1976, according to State Department officials, U.S. intelligence has reached the conclusion only in recent weeks that a functioning Soviet brigade, armed and organized as a combat unit, is in Cuba.

Since the intelligence finding was made public by Sen. Frank Church (D-Idaho) following a State Department briefing two weeks ago today, U.S. analysts have redoubled their research into the history, activities and possible role of the Soviet brigade. Additional information from files of the intelligence agencies has done little to clarify the shadowy aspects and in some respects has complicated the search for complete and clear conclusions, according to informed officials.

The possibility that the Soviet brigade serves as a model for training Cuban troops in large unit maneuvers was attributed to U.S. military intelligence. It is given a certain plausibility by reports that some Cuban units in Africa are deployed in the same configuration as the Soviet unit in Cuba.

The senior State Department official said that other possible missions for the Soviet forces include a "trip wire" against a possible U.S. invasion of Cuba, an expression of support for Cuban military activities in Africa, or a training device for Soviet troops assigned to tropical climates.