President Reagan was reminded again today by Sen. Jesse Helms (R-N.C.) of ambivalence around the country toward his tax revision plan, but Reagan campaigned before enthusiastic students here for what he described as another cut in tax rates similar to his 1981 tax cut.

Flying on Air Force One with Reagan to a speech at North Carolina State University, Helms told reporters that "with all due respect for my president" he didn't see much evidence of support for tax revision in this state.

Helms said most of the mail he has received on the subject has been negative. His comment seemed to dovetail with the assessment of Democrats and Republicans returning to Washington after the August recess that voters are more concerned about budget deficits and trade issues than tax revision.

Presidential spokesman Larry Speakes said in response to Helms that a negative response was due to a lack of understanding by most people. "It's complex," he said. "I don't think anybody opposes tax reform."

Reagan was well-received by 13,000 students and faculty here. He repeatedly advertised his plan as a tax rate cut -- not mentioning that some people would have to pay more under it -- a theme that appears to be getting more emphasis in this fall's speeches.

Reagan's proposal is designed to raise the same amount of tax revenue as the current system does. The plan would shift tax burdens somewhat from individuals to corporations. It would eliminate many popular tax deductions in exchange for lower tax rates.

By the administration's calculations, 58.1 percent of American families would realize a tax cut, 20.7 percent a tax increase and 21.2 percent would see no change under the proposal.

Asked to comment on polls showing that many Americans doubt that Reagan's plan will reduce their tax burden, Speakes said today:

"People are always concerned when Congress and an administration start dealing with taxes because they fear their own taxes will be increased. In this case, it's quite the contrary. There will be a tax reform bill and in this case the majority of taxes will be reduced."

Reagan told the crowd this afternoon, "The way our tax system is structured, the harder you work and the more you earn, the less you get to keep. One of the first priorities of our tax overhaul is to make sure that more of your hard-earned dollars will end up where they belong, in your wallets, not in Uncle Sam's pockets."

"Letting you keep more of what you work for, that's one thing fairness means," he added.

Amid the cheering students today were reminders of coming troubles for Reagan. Republican Gov. James G. Martin, in an indirect reference to textile industry demands for protection from imports, said in introducing Reagan that concern must be expressed for the "resilience and durability" of older industries as well as the emerging high-technology companies.

Also, there were scattered placards in the crowd denouncing South Africa's system of rigid racial segregation, known as apartheid. "Mr. President, Please See the Light on Apartheid," said one sign. Reagan has been resisting congressional efforts to impose economic sanctions on South Africa; he refused to answer reporters' questions about it today.

On taxes, Reagan said his first-term tax cut had helped create nearly 8 million jobs, and "on the theory that you can't have too much of a good thing, we're going to cut tax rates again."

"Our goal is a decade of economic expansion and 10 million more jobs in the next four years," he said. "With lower personal and corporate rates, and another cut in the capital gains tax, small and entrepreneurial businesses will take off.