Sen. Robert T. Stafford (R-Vt.), the incoming chairman of the Senate Environment and Public Works Committee, says he sees no need too change one of the major regulatory laws that his party and its presisdent-elect are dedicated to cutting back.

The Clean Air Act, which comes up for renewal in the next session of Congress, was a regular target of Ronald Reagan's campaign rhetoric, and Republican efforts to soften it are expected to provide one of next year's more rancorous legislative battles.

But far from endorsing the Reagan critisisms of the act, the courtly and easygoing Stafford regards the law's 1977 rewrite to its current status as his proudest achievement during nine years in the Senate. The 63-year-old-lawmaker may be from a rock-ribbed Republican state, but his self-described "pragmatic environmentalism may not be what the senate's new GOP majority is expecting.

I'm happy with the Clean Air Act as it is," he said in a recent interview. "I expect an effort to change it and the Clean Water Act . . . but I'd like to keep as many of those progams as we can."

Reagan campaigned against Clear Air provisions that he said stifle industrial growth by forcing costly emissions controls and banning new sources of air pollution in some areas. "I expect requests will be made to make changes, and it's possible some changes are needed," Stafford said. "I'll have to be convinced, but if I am I won't hesitate to move.

The act's critic's are expected to try to loosen standards for new pollution sources everywhere around major national parks and wilderness areas, extend compliance deadlines and guarantee no further regulatory changes for 10 years. Statewide requirements would be abandoned in favor of plant-by-plant emission limits.

Stafford said he supports the goals of rapid synthetic-fuels development and conversion of oil-fired facilities to coal-burning ones. "If we don't go ahead," he said, "we'll never escape OPEC, the Organization of Petroleum Exporting Countries. In contrast to many coal industry spokesmen, however, Stafford wants it all done under existing environmental controls.

"The technology is available to make [the coal conversions] with no added air emissions so that we don't increase acid rainfall," Stafford said. Unlike the coal industry, Stafford is convinced there is an acid rain problem from coal plant emissions, especially in many northeastern lakes.

Stafford's top priority recently has been a tough "superfund" bill to finance the cleanup of abandoned toxic waste dumps. With departing liberal John Culver (D-Iowa) and former senator Edmund S. Muskie, Stafford pushed a broad-based $4.2 billion proposal that was anathema to the chemical industry and to many conservative Republicans. But when it became clear that holding fast would mean no bill at all, Stafford engineered a compromise proposal that has revived prospects for enacting a measure this year.

I believe in getting things done. I understand that compromise is the name of the game up here. We have to be realistic," he said. "This is a more conservative and more business-oriented Congess coming in that will be less sympathetic to a very broad and strong superfund."

The complexion of the incoming Congress also means "a period of consolidation" for conservaative forces. "It's not an awfully good year for initiating new environmental programs," Stafford said.

Although he was regarded as a GOP liberal during his 11 years in the House and as governor of Vermont before that, Stafford calls himself a Republican moderate, noting consistent ratings of 40 to 60 percent from liberal as well as conservative congressional scorecard groups. A soft-spoken fellow, Stafford worked closely on the Environment Committee with Muskie, who was known as the environmentalist's champion on the committee before he left for the State Department. He agreed with Muskie on most issues, Stafford said.

Such views are not those of the new Republican majority. They reflect the GOP divisions over where the promised budget curbs and other cutbacks will come, and those divisions give Democrats some hope of forestalling major change.

In fact only five of 42 Republicans voted more often against President Ford in 1975 than Stafford did, and only six opposed President Nixon more in 1974. He has always enjoyed strong labor support in Vermont, where he was attorney general, lieutenant governor and governor.

But Stafford is no predictable liberal. He is a strong supporter of nuclear power as having "less impact, environmentally speaking, than almost any other energy source we have". He backs accelerated licensing of new plants: "The rest of the world is leaving us behind in constructing them."

He also supports continued funding for breeder reactor development at Clinch River, Tenn., although he is "somewhat concerned" that the particular design there may now be outdated. "I don't anticipate any difficulty with whatever Gov. Reagan wants in that area," he said.

Another Stafford priority next year will be a national water policy act. The traditional water project package, he said, has "operated on a hit or miss basis n the past, depending on the influence of the sponsor." President Carter established a "hit list" of blatantly pork barrel projects but only had limited success in killing them. Stafford would prefer to deal with the problem through an equitable distribution of projects, depending solely on the degree of water need in each area.

"Stafford is a true Yankee," summed up a comittee staff member. "He doesn't waste words and he always means exactly what he says . . . He studies an issue and once he makes up his mind he sticks with it." Other staff members called him easy to work with.

"He truly believes in regulatory reform," said one. "If a law doesn't work, he's willing to repeal it. He's open to new ideas. He's going to suprise a lot of people."