The House by a veto-proof vote of 349 to 55 approved a $1 billion emergency plan yesterday to help people buy new houses, the first piece of anti-recession legislation to get so far in this year's budget-conscious Congress.

The program, which the administration opposes as too costly, would pay for 4 to 6 percentage points of the interest rate on mortgages for 74,000 moderate-income new-home buyers. This would bring the rate down to as low as 9.5 percent for some, saving buyers tens of thousands of dollars over the five-to-seven year program. Benefiting buyers would have to repay these savings when their houses are sold or refinanced.

The bill passed yesterday is the program's first installment, covering the rest of this fiscal year.

While the immediate impact would be on the home-building industry and individual home buyers, House members justified the program as a quick jobs-producer and a ticket out of the recession.

"No single industry has as vital and direct an impact on jobs" as home building, said House Majority Leader James C. Wright Jr. (D-Tex.), estimating that one of every four jobs in the country is related to either housing or autos, the two industries that have been hardest hit by soaring interest rates.

"There is no alternative," he said. "We have to subsidize interest rates because we can't mandate that they come down."

The mortgage-interest subsidy has strong support on both sides of the Hill and both sides of the aisle, and some version of it is expected to be on the president's desk within the next few weeks.

President Reagan then would have a hard choice to make. While he has resisted a large-scale bailout for the housing industry, he could be hard put to veto a bill with so much bipartisan support on the Hill and popular appeal at the polls.

The Republican-controlled Senate Banking Committee earlier approved its version, for a 4 percentage point subsidy only, by a 15-to-0 vote, and the full Senate is expected to consider the legislation soon.

Unemployment in April was 9.4 percent nationwide, the worst since World War II, and joblessness in the construction industry was 19.4 percent. Proponents of the housing plan estimate that it would create 140,000 new jobs this summer, which would be enough to shave a little more than one-tenth of a percentage point off the overall unemployment rate.

The scattered opposition in the House yesterday to the measure focused on cost.

"This billion-dollar bailout has all the makings of becoming another multibillion-dollar boondoggle," argued House Minority Leader Robert H. Michel (R-Ill.). "We're again locking ourselves into subsidies for the next five to seven years when we should be dealing with economic problems in the next five to seven months."

Two Republicans--Reps. Thomas B. Evans Jr. of Delaware and Tom Corcoran of Illinois--had a plan of their own to subsidize rates in conjunction with tax-free mortgage revenue bonds. But they wanted to pay for the program with money taken from synthetic fuels programs, something the Democrats--particularly synfuel champion Wright--were unwilling to do.

Wright and others argue that the proposed transfer is a phony idea because the synfuels funds are in loan guarantees rather than in actual spending.

The program as adopted by the House would give a 4 percentage point subsidy to families with incomes up to 130 percent of the median income in their area and would provide a 6 percentage point subsidy to those up to 115 percent of median.

The maximum mortgage would be $67,500 generally, but could go as high as $90,000 in high-cost areas such as Washington. The money would be available through lenders and would be allocated according to a formula based on state population, decline in building permits and need for housing.

The House now has to agree to finance the program. An urgent supplemental appropriations bill that includes the $1 billion through the rest of fiscal 1982, to end Oct. 1, is scheduled for floor action today.

The second piece of the mortgage subsidy program, another $3.5 billion over the next seven years, starting in fiscal 1983, is part of a separate housing bill that was approved yesterday in the House Banking Committee. That bill also includes emergency aid to help home owners who have lost their jobs avoid foreclosure on their mortgages. The vote on the bill was 24 to 18.

The Senate's $5 billion five-year program is in one bill