Education Secretary Terrel H. Bell unveiled major revisions in handicapped education yesterday, proposing regulations that would allow schools to remove "disruptive" handicapped children from regular classrooms where they have been in the mainstream.

Critics say the proposals would return many youngsters to institutions and special classes for the mentally and physically handicapped.

The proposed changes would mark the first major revision of regulations implementing the Education for All Handicapped Children Act of 1975, which requires schools to keep handicapped students in regular classrooms as much as possible. Bell announced the proposals, which he said would streamline federal policy and reduce costs and administrative burdens on local school districts, in a news conference.

The revisions would permit schools to consider, for the first time, whether putting a disabled student in a regular classroom would result in "a substantial or clearly ascertainable disruption" to other students.

Shirley Jones, an Education Department attorney who helped draft the proposals and appeared at the news conference with Bell, said the disruption would have to be very serious, such as a hyperactivity or "head-banging" by a student. But Laura Pawle, an organizer in the Maine Association of Handicapped Persons, said the proposals would be an invitation for schools to exclude students in wheelchairs or those who are blind or have other disabilities.

"They're pretty disastrous," said Reese Robrahn, executive director of the American Coalition of Citizens with Disabilities.

Bell said the 4 million handicapped children in American schools, many of whom have only minor impairments such as hearing problems, would benefit from the revisions because they would increase the discretion given to local schools.

He stressed that the proposals are tentative and may be changed after comments are received in the next 90 days. Ten hearings around the country are also scheduled.

Schools frequently have protested that the federal regulations are burdensome and expensive to follow. But the handicapped and their parents have said that unless the federal government intervenes, schools discourage badly handicapped students from enrolling and shunt them into special, and often inferior, programs.

The principle of the current federal rules is to mainstream handicapped students wherever possible, by including them in regular classrooms and programs with all other students.

Jones said the department and the states would monitor schools to make sure they do not keep students out unnecessarily. She added that parents could also appeal any decision to exclude their children.

Many activists in the rights for the handicapped movement, which they compare to the civil rights or women's movements, do not trust the administration to uphold their interests. President Reagan last year tried unsuccessfully to cut by 25 percent the $1 billion in aid for education of the handicapped.

These activists are even less trustful of local school districts, and they strongly oppose giving more discretion to school administrators.

"I see it as turning the henhouse over to the foxes," Robrahn said.

Pawle said she had compared the proposed regulations with the ones they replace. In many cases protections currently in the rules are left out of the revision, and in some cases regulations are replaced by guidelines, which are not mandatory, she said. "We are outraged by these proposals," she said. "It looks like all the important rights of handicapped children and their parents are being completely gutted."

Among the changes she attacked:

Schools would no longer have to mainstream handicapped students in nonacademic programs. She said this would allow schools to segregate handicapped students at lunch and recess and in art or music classes.

* Schools would no longer have to pay for a second evaluation of a child, unless a hearing officer requested it. Now the school must pay for a second evaluation if the parents request it.

* Schools would no longer have to reevaluate children every three years. Instead, the proposed regulations say that the students must be reevaluated but leaves the period for the state to set.

* "Reasonable limits" could be placed on the services that schools provide handicapped students.

Jones said most of the revision was written before the Supreme Court decision in June in which the court held that the 1975 law does not require schools to provide services -- such as a sign language interpreter -- to maximize a handicapped student's learning potential.