Education Secretary William J. Bennett, supporting Reagan administration proposals to cut back low-interest guaranteed loans for college students, said yesterday that an estimated 13,000 students from families with incomes over $100,000 are receiving such aid.

Bennett's figures, based on a nationwide survey last fall of college freshmen, brought sharp criticism from Democrats on the House Education and Labor Committee. They said he was using extreme examples to "destroy" the program which aids about 3.4 million students this year.

In a speech last week President Reagan said the present program with a sliding scale of eligibility requirements based on college costs and family income "defies common sense" and "insults simple justice" by having the "least affluent" taxpayers subsidize the sons and daughters of the wealthy at high-cost private universities.

Under the proposals, the subsidized guaranteed loans, which carry 8 percent interest and are repayable after students graduate, would be limited to those from families earning under $32,500 a year. The plan also would restrict grants, work-study jobs and other federal aid to those with family incomes under $25,000.

A $4,000 maximum annual limit would be placed on any student's total federal assistance, although Bennett said yesterday that students also could receive up to $4,000 a year in unsubsidized loans with a federal guarantee. These now charge 12 percent interest.

The administration has estimated that its proposals would cut out about 20 percent of the 5.3 million college students receiving federal aid, a number that has grown rapidly since the late 1970s.

At the House committee hearing, Rep. William D. Ford (D-Mich.), chairman of the subcommittee on post-secondary education, said the cuts in the low-interest loan program would save just "130 million blood-soaked dollars" next year, but would cause a "tremendous burden" to poor and middle-income families.

Bennett responded that the savings would be much greater in future years. About $7.5 billion is expected to be loaned to college students under the program this year, with the federal government spending about $3.7 billion, most of it for subsidies and default payments on $35 billion in outstanding guaranteed loans. Bennett said the proposed cuts aim to reduce the federal deficit, concentrate federal aid on the neediest students and hold down the rise in college costs.

But Rep. Chester G. Atkins (D-Mass.) said the proposals were "a mechanism to detroy all the financial aid in the country." Paraphrasing Bennett's comments several weeks ago that the cuts might cause a "divestiture" of student stereos and cars, Atkins said the plan would lead to a "divestiture of hope, a divestiture of equality and a divestiture of opportunity."

During the contentious three-hour hearing, Bennett also strongly advocated a proposal to give give vouchers to low-income families, whose children now receive aid under the Chapter I program. The vouchers could be used for private school tuition or to supplement regular public school programs.

Rep. Augustus F. Hawkins (D-Calif.), chairman of the Education and Labor Committee, said the proposal would help "undermine public education" and would encourage the "proliferation of fly-by-night" private schools.

But Bennett said the plan would give poor parents more opportunities to improve their children's education.