The Environmental Protection Agency has agreed to slice nearly 80 percent out of this year's budget for a project designed to help measure the cost of pollution controls to curb acid rain, despite the Reagan administration's pledges to make such research a priority.

The cutback, ordered by the Office of Management and Budget, means that the project will not be completed this fiscal year. EPA did not appeal the OMB directive, which will cut funding for the Advanced Utility Simulation Model program from $650,000 to $150,000.

"It's a tiny item in terms of bucks," said OMB spokesman Edwin L. Dale Jr., who said the money would be transferred to a similiar research project involving non-utility polluters.

But the decision was viewed by some environmentalists yesterday as a sign that neither OMB nor EPA is interested in scientific data that might run counter to administration policy. Sulfur dioxide emissions from coal-fired power plants are believed to be the major contributor to acid rain. Utility companies, citing their own studies, say the costs of reducing the emissions would be monumental. The project would have provided a tool for the government to determine those costs for itself.

"They're beginning to panic," said an official with the National Wildlife Foundation. "It's another indication that the administration wants only research that is consistent with their position."

Sen. Daniel P. Moynihan (D-N.Y.), in letters to EPA Administrator Anne M. Gorsuch and OMB Director David A. Stockman yesterday, said the budget reduction "seems completely unjustified" and "calls into question this administration's commitment to carry out an effective acid rain research program." Moynihan reminded Gorsuch that EPA's budget request for this year "highlighted the progress being made in the model's development . . . and that the model would soon be ready for operation at the national level."

Researchers involved in the project, meanwhile, were bewildered.

"It's a devastating thing," said Dr. James Stukel, a University of Illinois researcher who has worked on the project with colleagues at two other universities. "We're on schedule. We would have delivered to the acid precipitation task force on time. Now we will not be able to deliver."

Stukel said the project, which has already cost the government $2 million, was in its third and final year. He said he and his colleagues were assured in early November by Courtney Riordan, assistant administrator of EPA for research, that "all they had to do was dot the 'i's in the grants."

Two weeks later, he was told the project would be cut.

OMB spokesman Dale said EPA already had a similar model for estimating the costs of environmental controls to utilities, but Stukel said, "If they have one, I don't know about it. Why would they spend $2 million on ours if one already existed?"