The House yesterday began tackling trade legislation that Democrats see as an issue that could gain them more House seats and control of the Senate in the November election.

The debate opened in an unusual partisan atmosphere as Republicans accused the Democratic majority of playing party politics with trade.

But Minority Leader Robert Michel (R-Ill.), who is pushing a tough Republican measure of his own, predicted that some GOP members would cross party lines and vote for the Democratic bill out of concern that trade will be a major issue in their districts in the fall campaign.

The Reagan administration, which has attacked the bill as protectionist and threatened a veto, is trying to keep House Republicans from supporting the Democratic legislation. Its efforts are undercut, however, by the White House's lukewarm attitude toward the Michel bill even though the Reagan administration considers it far less protectionist than the Democratic alternative.

Rep. William Frenzel (R-Minn.), one of the leading advocates of free trade in the House, described the Democratic measure as "an issue rather than a serious bill." He said the administration would have liked to work with House members to craft an acceptable trade bill, but the Democratic leadership decided to go off on a partisan track.

U.S. Trade Representative Clayton Yeutter said Democrats are focusing on trade because President Reagan's economic policies have left them with little else to attack. The U.S. trade deficit, which reached a record $148.5 billion last year, has nearly quadrupled between 1982 and 1985, totaling $400 billion during that four-year-period.

Opening the debate, Ways and Means Committee Chairman Dan Rostenkowski (D-Ill.) called the 458-page trade bill "an all-out congressional offensive to modernize and restructure American trade policy -- and to check unfair trade practices that are costing this country jobs and a secure economic base for the future."

Responding for the Republicans, Rep. John J. Duncan (R-Tenn.) called the measure "an overreaction . . . loaded with provisions that in the very least are questionable."

Under a schedule worked out by the leadership, there will be votes today on eight of some 13 amendments.