U.S. Trade Representative Clayton K. Yeutter said yesterday there is less than a 50-50 chance that Congress will craft a trade bill acceptable to President Reagan and listed seven major administration objections to the bill that is scheduled to go before the Senate as early as next week.

Yeutter told a U.S. Chamber of Commerce International Forum that there is a possibility of combining the House and Senate bills in a way that would produce legislation acceptable to the administration.

"Where we are troubled by the Senate bill, the House bill is much more acceptable to us, and visa versa. There is a chance of picking the best of both and putting them together," Yeutter said.

"We are not going to emerge with a protectionist bill. If we do, the president will veto it," he warned.

As Yeutter spoke to the business organization, Senate Majority Leader Robert C. Byrd (D-W.Va.) told Senate Democratic leaders that he won't allow a trade bill to be weakened to avoid a veto.

"I'd like to see the president sign the bill, but if he doesn't we'll just have to pass it over the veto. But I think we are going to have a good bill," said Senate Finance Committee Chairman Lloyd Bentsen (D-Tex.). He added that he doesn't expect the president to like all parts of the bill and pointed out that the legislation will be the result of a bipartisan congressional compromise.

Byrd said he wants trade legislation approved by eight Senate committees combined into one major bill, which could come up for an estimated two to three weeks of debate starting next week or the week after. Staff members are working this week to produce one bill for Senate consideration.

Sen. Donald W. Riegle Jr. (D-Mich.), meanwhile, is seeking bipartisan support for an amendment designed to attack trade surpluses produced by unfair trade practices. He said his amendment would force countries with "supersurpluses" to eliminate within three years the portion of the surpluses resulting from unfair trade practices. In the case of Japan, he said, $15 billion of its $60 billion surplus last year came from barriers to U.S. products and other unfair trade practices.

Riegle said the nations that would be affected by his proposal are Japan, Taiwan and South Korea.

The Riegle proposal differs from one passed by the House and pushed by Rep. Richard A. Gephardt (D-Mo.) and organized labor that aims at eliminating the entire surplus, not only the portion that results from unfair trade tactics.

The Gephardt amendment drew the heaviest criticism from the administration. Riegle said his proposal will be harder to oppose because "it sets up a debate between people who say trade barriers must come down and those who would defend the barriers."

In his speech, Yeutter took aim at parts of the bill that he said worry the Reagan administration. These provisons would:Make it easier for industries injured by import surges to get help through quotas or tariffs. Yeutter said the Senate bill would "emasculate" the president's power to refuse to help a domestic industry if it would hurt the overall U.S. economy. Other countries, moreover, would likely pass similar legislation that would reduce U.S. exports, he said. Allow the government to block foreign investment to protect "national security or essential commerce." Yeutter said part of the bill conflicts with U.S. efforts in international trade talks to remove barriers to the global flow of investment. Besides, he added, "we need the investment flows" to finance the U.S. budget deficit. Require the president to keep petroleum imports below 50 percent of domestic consumption through means that could involve an oil import tax. Yeutter called the measure, pushed through the Finance Committee by Bentsen, "sheer protectionism." Force presidential retaliation against countries using unfair trade practices. Yeutter said that provision would reduce the flexibility needed in negotiations. Restrict the president's negotiating authority in global trade talks. Yeutter said the administration is pleased with the authority in the House bill but not with the limitations the Senate proposal contains. Finance worker-adjustment assistance through a "small" tax on imports that Yeutter said could lead to similar taxes all over the world that would hurt U.S. exporters. Force companies to tell workers in advance if they plan to close a plant. Yeutter said such legislation would hurt U.S. competitiveness.