President Reagan is preparing to sign the first set of appropriations bills Congress has sent him this year, postponing until later this summer his threatened confrontation with Capitol Hill over "budget-busting" money bills that exceed his request.

The White House announced yesterday that Reagan intends to sign a $55.8 billion appropriations bill this week for the Department of Housing and Urban Development and 17 independent agencies, even though it exceeds his request by $6.2 billion, mostly for subsidized housing.

Administration officials said that Reagan also will sign the $1.5 billion appropriations bill for legislative activities. The officials said that the president may sign a $14.3 billion spending measure for energy and water programs, although a final decision hasn't been made.

House-Senate conferees made several concessions on the HUD-independent agencies bill that cleared the way for Reagan's signature. They agreed to a request by Office of Management and Budget Director David A. Stockman to hold the number of new subsidized housing units to no more than 100,000. The administration had sought funding for 90,000 units. The House version of the bill went as high as 116,000 units, and the Senate version 112,000 units.

Appropriations for the subsidized housing program are voted all at once for the life of the housing: 20 years or more. Thus, the addition of a few thousand units added billions of dollars in subsidies to the appropriations bill, pushing the total beyond the administration's request.

OMB spokesman Edwin L. Dale Jr. said that the administration accepted the HUD money bill because the outlays for subsidized housing are stretched out over 20 or more years.

The conferees also bowed to Stockman's request that they delete $150 million for a new program of direct mortgage loans to veterans, and another $150 million for a new job training program for veterans. Both have been authorized by the House but not the Senate.

Meanwhile, civil rights groups and Sen. Edward M. Kennedy (D-Mass.) yesterday criticized Reagan's announcement that he will propose changes to toughen the enforcement provisions of the 1968 Fair Housing Act. The president, who on Saturday said he would put "real teeth" in the law, will submit details of his proposal today, the White House said.

In a letter to members of the House, a coalition of 165 national civil rights groups charged that Reagan's proposal would result in "costly, lengthy and inefficient" lawsuits that would add to the already heavy caseload of the federal courts.