President Reagan spent his first full day in the Oval Office yesterday, held a Cabinet meeting devoted to the economy and took part in another swearing-in ceremony, this one for his senior White House aides.

In other actions on Day Two of the new administration, the Senate confirmed four Cabinet members, it was reported that obstacles to the confirmation of another seemed to have disappeared and a Reagan economic aide said the administration would move quickly to remove federal price controls from crude oil and gasoline.

The Senate approval Alexander M. Haig Jr., 93 to 6, to be secretary of state and unanimously approved Donald Regan to head the Treasury Department, Richard Schweiker to lead the Department of health and Human Services and Bill Brock to be U.S. trade representative. [Details on Page A12]

David Stochman, Reagan's choice to head the Office of Management and Budget, said oil and gasoline prices will be decontrolled soon, which could lead to an increased of 12 cents a gallon at the gas pump if all the increase is passed through.

Sen. Orrin G. Hatch (R-Utah) said the FBI has been unable to substantiate allegation against Reagan's choice to head the Labor Department, Raymond Donovan.

Reagan aides said he will now be able to abolish the inflationable to abolish the inflation-monitoring Council on Wage and Price Stability in his first few days in office, as he had planned and promised.

Reagan reminded his Cabinet members that his first presidential action Tuesday had been to order a freeze on federal hiring and urged them to observe the freeze as a step toward controlling the federal budget. Most of the 93-minute-long meeting was devoted the the budget.

"We've got to get control of the budget. . . . It is out of control," Reagan said as he began the meeting.

After the Cabinet meeting, White House officials announced the leaders of South Korea and Jamaica will be the first two heads of government to pay official visits to Reagan.

Reagan, appearing fresh and enthusiastic after his long night of inaugural celebrations, began his first full day a president with another ceremony.

He and Vice President Bush attended the East Room swearing-in of the senior White House staff members.

Reagan entered with a Marine band playing "Hail to the Chief" and spoke briefly to the staff members and roughly 150 members of their families who sat on gilt chairs to watch the group take the oath in unison.

"I want you to know that I don't expect every morning to be greeted by the Marine Band," Reagan said. He noted that many of those who are now White House staff members once belonged to his gubernational staff in Sacramento or to his 1976 or 1980 campaign staff.

White House Chief of Staff James A. Baker III, who acted as master of ceremonies, said he hopes the presidental staff will be no larger than the 351 people on President Carter's staff.

Baker added that the Reagan administration intends to reverse the trend since the Eisenhower administation by trimming 10 percent of the jobs from the 1,700-member executive office of the president. About 200 of those jobs could be eliminated by abolishing the Council on Wage and Price Control.

Reagan promised over and over during the campaign to have a strong Cabinet and restore Cabinet members role in decision-making. Baker said yesterday, "A strong White House staff and a strong Cabinet are not mutually exclusive."

Chief Justice Warren Burger administrated the oath to the 38 staff members who included Baker and Edwin Meese III, the counselor to the president who is the only staff member also a member of the Cabinet.

Reagan gave his Cabinet a brief report on the 52 Americans released from Iran. He called them prisoners of war as he has done consistently, although Brady and a senior White House official insisted yesterday that Reagan's refusal to use the term "hostages" does not have any significance as to how the Reagan administration will deal with Iran in the future.

In addition to the portraits of Presidents Eisenhower and Coolidge that have replaced those of Presidents Truman and Jefferson in the Cabinet Room, there was another new item -- an 18-inch-tall jar of multicolored jelly beans.

Reagan said he got the Waterford crystal jar in Ireland and he urged his Cabinet members to enjoy his favorite candy. On long, weary afternoons, Reagan said, "when you need some energy I expect to see the jar going around the room."

Prince Minister Edward Philip George Seaga of Jamaica will be the first government leader to visit Reagan at the White House. Seaga defeated Michael Manley in an October election and promised to seek closer ties with the United States. He will visit Reagan Wednesday.

President Chun Doo Hwan of South Korea will visit Reagan Feb. 2. In arranging the visit, U.S. and Korean officials discussed the case of Kim Dae Jung, the Korean opposition politician who is under a death sentence. Reagan has urged that Kim not be executed. A senior White House official said yesterday the Kim case would be on the agenda when the Korean leader arrives in Washington.

Reagan had arranged earlier for King Juan Carlos of Spain and Prime Minister Margaret Thatcher of Britain to visit in February. A senior official said a Reagan meeting with Canadian Prime Minister Pierre Trudeau in the near future is under discussion. CAPTION: Picture 1, President Reagan presides over the Cabinet meeting yesterday, flanked by Secretary of State Alexander M. Haig Jr. and Defense Secretary Casper W. Weinberger. By Frank Johnston -- The Washington Post; Pictures 2 and 3, Reagan attends swearing-in of White House staff members. With him are: Edwin Meese III, counselor, James A. Baker III, chief of staff, and Martin Anderson, domestic adviser. Secretary of State Haig sits beside Reagan at Cabinet meeting. AP; Picture 4, Speaking of the Waterford crystal jar filled with jelly beans, Reagan told Cabinet members, "When you need some energy I expect to see [it] going around the room." By Frank Johnston -- The Washington Post