The House reached back a half-century yesterday to revive a major New Deal jobs program as it approved, 301 to 87, the creation of a conservation corps to employ as many as 100,000 young people a year in parks, forests and Indian reservations.

The vote for an American Conservation Corps, patterned after the Civilian Conservation Corps of the 1930s, came over the opposition of the Reagan administration, which has largely dismantled two recent similar programs, the Youth Conservation Corps and Young Adult Conservation Corps.

The bill now goes to the Senate, where a similar House-passed proposal last year died.

Although relatively small, only about one-fifth the size of the CCC program at its peak in the Great Depression, the program is the first of several job-creating measures being considered by the 98th Congress in response to the recession's continued high unemployment.

Money to fund the program, up to $60 million this year and $300 million for each of the next five years, would have to be provided later.

The funding would be in addition to a $4.6 billion "emergency" appropriations for jobs that is expected to be approved by the House Thursday.

There were indications yesterday that this measure, for which President Reagan has signaled qualified approval, may be expanded on the floor to nearly $5 billion.

Rep. David R. Obey (D-Wis.) was expected to push for $200 million more for health care services, and Rep. James J. Howard (D-N.J.), chairman of the House Public Works and Transportation Committee, who opposed the bill in its present form, wants expansion and redistribution of funding for transit projects.

Other members were also proposing add-ons, and the Rules Committee, under pressure from the leadership to prevent the bill from growing bigger than Reagan will accept, is scheduled to meet today to consider which amendments to allow on the floor for a vote.

In the vote on the American Conservation Corps, all but five Democrats supported the measure, while Republicans split: 70 for it, 82 against it.

"This is real work that needs to be done...real, not just make-work," said Rep. John F. Seiberling (D-Ohio), noting what he called a huge backlog of work in reforestation, trail building and bridge repair that could be done by jobless young people. "Greater bang for our bucks" than other jobs programs, said Rep. Silvio O. Conte (R-Mass.).

Rep. Trent Lott (R-Miss.), the House minority whip, conceded that the bill made "political sense," but suggested that it would result in "makeshift-type work," duplicate other programs and add to budget deficits.

"This is a perfect symbol of the old politics of the 1930s," complained Rep. William Frenzel (R-Minn.), predicting "probably the most expensive jobs we've ever had."

The program would be open to unemployed people ages 16 to 25 for year-round jobs and 15 to 21 for summer work. Special consideration would be given to disadvantaged youth from high-unemployment areas. Jobs would be limited to 24 months per worker.

States would receive 35 percent of the program, Indian tribes 5 percent and federal agencies, principally the Interior and Agriculture departments, the rest. Projects would include forestry, rangeland conservation, improvement of recreation areas, preservation of historical and cultural sites, urban revitalization projects and energy conservation.

Meanwhile, at the behest of Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass.), House Democratic leaders began a series of meetings aimed at producing an alternative to Reagan's budget.

Reagan was able to capitalize on Democratic divisions to get his budget through the House in 1981 and 1982, but the November elections strengthened Democratic ranks to the extent that Democrats now say they believe they can pass a budget of their own.

O'Neill's move yesterday gives the party's Steering and Policy Committee, as well as major committee chairmen, a more important voice in budget-making.