The movement to restructure the federal tax system survived a brush with death in the House last week, but to paraphrase President Reagan, "it ain't seen nothin' yet."

The problem is not so much that the Senate, which takes up the House-passed tax bill next month, has 22 Republican members up for reelection and facing more-than-usual pressures from corporate contributors opposed to tax overhaul.

Nor is it that the politics of deficit reduction and the search for more federal revenue threaten to subsume the tax measure in the Senate.

The biggest obstacle to a bill aimed at shifting $140 billion of the tax burden from individuals to corporations in the next five years is, in the view of administration officials and political scientists, the personality of the Senate itself.

Unlike the House, where rigid rules allow only brief debate and few amendments on tax bills, the Senate floor is a sort of free zone where members can offer unlimited amendments and filibuster until a two-thirds majority of colleagues votes to shut them up.

"Anybody can offer any goofy thing he wants to," said former senator Gaylord Nelson (D-Wis.), who along with then-senator Walter F. Mondale (D-Minn.) and Sen. Edward M. Kennedy (D-Mass.) offered numerous ill-fated amendments to curb corporate tax breaks in the 1970s.

Tax overhaul, as defined in the House bill and in Reagan's proposal, aims to close loopholes benefiting a wide range of corporations and wealthy Americans, and to use the extra revenue to reduce tax rates for individuals and businesses. The theory is that the existing system favors some corporations and individuals over others, hampering overall economic growth. Critics contend that the proposed changes would make things worse.

House Ways and Means Committee Chairman Dan Rostenkowski (D-Ill.) set a strategy of curbing enough tax breaks to give his panel's bill an impartial flavor, and then made concessions to pick up needed votes. While most members, including Rostenkowski, had certain objections to the measure, rigid House rules intended to impose order on the 435-member body forced them to take it -- warts and all -- or kill it.

The Senate has no such built-in pressure to conform. Designed by the Founding Fathers to safeguard the interests of each state, it is home to 100 independent operators.

Sen. Russell B. Long (D-La.), ranking Democrat on the tax-writing Senate Finance Committee, said the panel generally tries to accommodate the interests of each member -- oil, minerals, timber, real estate, basic industries. Committee Chairman Bob Packwood (R-Ore.) has said he will push to restore favorable tax treatment for the timber industry, the biggest private employer in his state and one that would be hit hard by the House bill. Long said he and others will do the same for oil.

Because of this pattern, past House bills curbing corporate tax benefits generally have had those benefits restored in the Senate. In 1969, for example, the House voted to eliminate the oil depletion allowance; the Senate put it back. (It was curbed, but not eliminated, in the final bill.)

Moreover, the modern-day Senate Finance Committee has several of its own ideas about what constitutes tax overhaul, and some of them conflict with Reagan's.

Packwood and Sen. William V. Roth Jr. (R-Del.) advocate a consumption tax to raise revenue outside the income tax system. Others advocate gas taxes or oil import fees, while Sen. John H. Chafee (R-R.I.) has pressed for reducing most existing tax benefits by 25 percent. Sen. Bill Bradley (D-N.J.), who introduced his own tax-overhaul measure two years before Reagan, is the most enthusiastic supporter of the House measure although he too seeks numerous changes.

Another signal of Senate independence came last week in response to Reagan's letter to House Republicans -- a written promise to veto the tax bill unless the Senate changes it to his specifications. Majority Leader Robert J. Dole (R-Kan.) and Packwood said they would not be bound by Reagan's dictates.

"We'll see what he vetoes and what he doesn't," said Chafee, a Finance Committee member. "There's too much talk of vetoes around here."

Despite this history, several senators said in interviews that they believe tax overhaul along the lines etched by Reagan and the House is possible in 1986. The chief factor is Reagan, who plans to promote the measure in his State of the Union address and to make it a key issue in the 1986 Senate elections.

"I think the Senate is in the mood for this legislation because of the attraction of lower tax rates and also because we're the president's party and we want to accommodate him to the best of our ability," Chafee said.

He and other senators in both parties emphasized, however, that they expect to build in more benefits for business investment -- one of Reagan's criteria and an approach that many House Democrats said they applaud.

Bradley, who is expected to take a prominent role in the debate, predicted that the lure of lower tax rates in an election year could ease the tougher decision to curb tax benefits.

"In the past, when the Senate added a lot of loopholes to the tax code, we were living in a world without $200 billion deficits," Bradley said. "Today, if you want to make the speech for lower tax rates, you have to make the speech for closing loopholes, too."

He and others pointed out that the Finance Committee has made that kind of tradeoff before -- in 1982, under then-chairman Dole, when it narrowed numerous loopholes to stem revenue losses from Reagan's 1981 tax cut. At the time, 12 of the panel's 20 members faced reelection.

Perhaps the biggest political wild card is the Gramm-Rudman-Hollings law mandating deficit reduction, whose first effects will be felt as the Senate is grappling with the tax measure. If congressional budget cuts do not pare the deficit to targeted levels, new tax revenues could be needed, and the overhaul bill could become a vehicle for them if political pressure mounts.

"As an economist," said Harvey Galper of the Brookings Institute, "I'm finding the politics of this bill as fascinating as the economics."