Sen. Alan K. Simpson (R-Wyo.) unveiled a comprehensive immigration bill yesterday and predicted that it will do better in Congress than last year's version, which died after heavy lobbying by Hispanic groups, farmers and unions.

Simpson acknowledged that his new measure contains many of the same provisions that drew such strong opposition in the House last year.

But he said that most lawmakers want to stop the flow of illegal aliens and that with elections still more than a year away, they will be more willing this year to tackle the controversial subject.

Last year, the immigration bill was caught in the cross fire of the presidential campaigns, when Democratic nominee Walter F. Mondale, under pressure from Hispanics, came out strongly against it and the Reagan administration gave it only lukewarm support.

Approval by the Republican-controlled Senate is likely; the Senate voted for Simpson's bill last year and the Wyoming Republican said he will press for a vote there before the August recess.

In the Democrat-controlled House, the bill faces much dimmer prospects. After repeated delays by the House Democratic leadership in bringing the bill to the floor last year, it was narrowly approved after days of intense, emotional debate. It then died in a conference with the Senate, when House members balked at making changes Simpson wanted.

Signifying the trouble it is likely to encounter, the bill was quickly attacked by Hispanic lawmakers and lobbyists as well as some growers.

"It's disappointing and regressive from the point of the bill last year," said Rep. William B. Richardson (D-N.M.), chairman of the Congressional Hispanic Caucus.

Last year's measure would have provided immediate amnesty for illegal immigrants. Simpson's new bill would delay amnesty until a program of stiff fines against employers hiring illegal aliens had a chance to become effective.

The sanctions would range from a warning for the first offense to a $10,000 fine per illegal alien for an employer who continued to hire undocumented workers. Hispanic groups said last year that sanctions would increase job discrimination against Hispanics.

Simpson said he altered the legalization provision because it had been one of the major reasons some conservative lawmakers had voted against the bill last year.

In an effort to deal with Hispanic concerns about possible discrimination, Simpson's bill would have the General Accounting Office monitor the situation. The attorney general, along with the Civil Rights Commission and the Equal Employment Opportunity Commission, would then review GAO findings.

In an effort to respond to the concerns of growers, many of whom bitterly opposed last year's bill, Simpson's measure would allow growers to bring in temporary foreign workers on a somewhat expedited basis if growers could not find enough U.S. workers or faced unexpected harvest conditions