President Reagan promised yesterday to veto the House-passed trade bill, which he denounced as "kamikaze legislation" that could take millions of American jobs "down in flames."

"The so-called omnibus trade bill is really an ominous antitrade bill that could send our economy into the steepest nose dive since the Great Depression," Reagan told the National Association of Manufacturers in a speech that also contained a staunch defense of his administration's trade policies.

But his strongest rhetoric was devoted to an attack on the wide-ranging trade bill, which passed the House, 295 to 115, with 59 Republicans supporting the Democratic-sponsored bill.

The president's attack appeared to be aimed at the Republican-controlled Senate, which is likely to consider trade legislation this summer. The Senate bill is expected to eliminate some of the provisions of the House bill that Reagan finds most objectionable, but would likely still take a tougher line than Reagan on unfair trade practices.

Reagan called the House bill worse than protectionism. "It's destructivism," he said.

"This reactionary legislation would force American consumers to pay billions in higher prices, throw millions of Americans out of work and strangle our economy as foreign markets slam shut in retaliation."

The president's attack drew an immediate response from House Democrats, who see trade as an issue that could gain them more seats in the House and possibly enable them to wrest control of the Senate from the GOP in November.

"Fear of retaliation didn't stop Reagan from bombing Libya. The trade war is just as real as the war against terrorism, and the Democrats don't want to surrender either one," said Rep. Tony Coelho (D-Calif.), chairman of the Democratic Congressional Campaign Committee.

"If our trade bill is being called kamikaze, then it is aimed at the right targets -- unfair trade practices," added Rep. Don Bonker (D-Wash.) who was sitting on the podium during the Reagan speech. "It is because of the administration's failed policies that we are losing the trade war."

The audience sat silently during Reagan's speech, reflecting the split within American business over how to react to record trade deficits, which reached $148.5 billion last year.

Reagan staunchly defended his trade policy, which, he said, is designed to promote free trade, move aggressively against unfair trade practices that hurt American industries and correct the underlying economic reasons for the trade imbalance, such as the overvalued dollar and slow growth in the world.

"America doesn't need to hide behind trade barriers," Reagan said. "Given a level playing field, Americans can out-produce and out-compete anyone, anywhere on earth. That's why it's the policy of this administration to open markets abroad, not close them at home.

"We will bring the world with us into into a new era of free trade," Reagan continued. "Free trade -- with free traders -- is our byword."

He defended his administration from charges that it has a do-nothing trade policy, saying instead that it is "more activist, more aggressive than any other in blowing the whistle on unfair trade practices against American producers.

"From insurance in Korea, to computers in Brazil, to tobacco products in Japan, this administration is making sure that American exporters get a fair shake abroad," Reagan said.

At the same time, he said, the administration is acting on the underlying causes of the trade imbalance, moving in September to bring down the overvalued dollar, considered by economists the major cause of America's trade deficit.

He said U.S. economic growth -- stronger than any other in the world -- created 10 million new jobs, more than Europe and Japan combined, "but this House bill would start wiping them out." He added that 5.5 million U.S. jobs dependent on exports "would be threatened if this bill were passed into law."

Among the "first victims" the president mentioned were aerospace engineers at the Boeing Co. plant in Seattle; recording engineers at CBS Inc.'s record division; wheat farmers in Nebraska and longshoremen in New Orleans who load grain on ships.

Earlier, R. E. Heckert, chairman of the E. I. du Pont de Nemours and Co., told a NAM audience that the House trade bill "indicates the depth of frustration felt by Congress and the public, and our leaders should take notice.

"But more to the point," Heckert continued, "the flurry of activity surround ing the bill reflects the continuing dynamics of trade policy in our government: Congress acts, the administration reacts."

In comments that were unusually tough coming from the chief executive of an export-oriented, multinational company, Heckart said that "free-trade rhetoric, even with improved economic policy, will make it difficult or impossible to achieve an acceptable trade balance in a reasonable time frame."

He defended trade barriers when necessary, questioned why it took the administration until September to move on growing trade imbalances and suggested that American consumers "help restore some balance to the trade accounts by choosing whenever possible from among the high-quality goods manufactured in this country."

In a White House briefing following the president's speech, aides defended Reagan from charges that some of his policies -- including actions announced within the past two weeks against Brazil, Western Europe, Japan and Canada -- are as protectionist as anything in the House bill.