President Reagan announced yesterday that federal employes will not have to pay for parking, ending a controversy that began two years ago when the Carter administration ordered that fees be charged for previously free parking spaces.

"Ho, ho, ho, Merry Christmas!" said a jubilant Rep. Stan Parris (R-Va.) who was one of three area Republican congressmen summoned to the Oval Office to be told of the president's decision.

Reagan's announcement came two days after the U.S. Court of Appeals here ruled that President Carter acted legally when he imposed the controversial fee program, which was supposed to generate $40 million in revenue and encourage the use of mass transit.

A White House official said the decision means not only that the fees will not be resumed, but that the government will not attempt to recoup an estimate $15 million in fees that went uncollected while the issue was in the courts.

The fee program infuriated many of the area's 75,000 federal workers who drive to their jobs and could have been required to pay as much as $90 a month.

"It was one of the most unpopular things Jimmy Carter did to federal workers," said first-term Rep. Frank Wolf, who lobbied the president along with Parris and Rep. Marjorie S. Holt (R-Md.) to abolish the program.

The three spent l5 minutes with Reagan yesterday pleading their case and munching jelly beans before he told them he agreed.

"To resume those fees would impose yet another financial burden upon thousands of hard-pressed federal employes who have had only 4.8 percent increases in their pay," the president said in his statement. Many workers, Reagan said, have "limited access to public transportation and appreciate the flexibility and security of automobiles."

"It's really refreshing to have a friendly ear in the White House," said Parris. "I'm delighted by the president's decision."

Officials of federal employe unions, which had challenged the parking fees as well as Reagan administration cutbacks in social programs and health insurance benefits, reacted with more restraint.

Vincent L. Connery, president of the National Treasury Employees Union, said "We are pleased that federal employes will be spared the added financial burden of parking fees. It is, however, little comfort to workers who are already suffering due to reductions in force, downgradings, and the inadequate 4.8 percent pay raise which President Reagan handed out last October."

Kenneth T. Blaylock, president of the American Federation of Government Employees, the largest union in the Washington area, said that the decision "is the kind of personnel policy that ought to be made, if this administration wants government workers to believe again that this administration understands the problems workers face."

Wolf, who represents more active and retired federal workers than any other representative and has been criticized as "hostile and unresponsive" to the area's bureacrats, was happy with the decision. "I think this will help me with federal employes," he said.

"The program just wasn't cost effective," Holt said. She said the nationwide parking program would have cost the government nearly as much money as the $40 million it was expected to raise.

When the program began in November l979, employes who had parked free were required to pay half the commercial rates in the neighborhoods where they worked, a figure ranging from $12 to $45 in the Washington area.

Under that schedule, employes would have been required to pay the full commercial rate by October 1982.

Carter had imposed the program despite the warnings of some aides who said the program could have "adverse effects on the morale of federal workers," some of whom picketed the White House. The former president imposed the program anyway and placed it under the 1975 Energy Policy and Conservation Act.

Exempt from the program were areas surrounding the White House, congressional spaces on Capitol Hill and VIP spaces near the terminals at Dulles and National airports.