Education Secretary William J. Bennett said yesterday he will propose legislation "within two weeks" to establish a voucher system that would give money directly to impoverished parents to pay for remedial school help for their children who need it.

Such aid is now given to school districts under a $3.2 billion program known as Title I of the Elementary and Secondary Education Act. The Supreme Court, in landmark rulings last week, said public school systems may not use that money to send teachers into parochial school classrooms.

In two separate rulings involving school districts in Grand Rapids, Mich., and New York City, the court said such use of federal money would result in an "entanglement" of church and state.

Bennett said yesterday he will not be deterred by those rulings, and might even be able to turn them into an argument in favor of his controversial voucher plan. "The Supreme Court decision arguably strengthens our case," he said.

"I don't think that, as a result of the Supreme Court decision, Congress is going to be any less interested in getting these funds to these students," he said. Giving the money directly to parents, in the form of a voucher, may be one way around that court ruling, he said.

Bennett and his undersecretary-designate, Gary Bauer, said that by targeting the voucher plan only to the remedial instruction program they hope to enlist the support of the poor and the disadvantaged. They said they want to dispel the notion that voucher plans benefit upper-middle-class families that send their children to expensive private schools. "We're getting the word out to low-income parents," Bauer said. "We think that's a point we need to be more aggressive in making."

Bennett said the voucher plan was being drafted before the court's ruling, and now is being reviewed to see if it contains any provisions subject to a similar constitutional challenge. At the time the high court ruled, Bennett said the justices displayed "a fastidious disdain for religion which for me is hard to fathom."

Bennett and Bauer made their remarks yesterday in an interview over lunch in the secretary's fourth-floor dining room. During the informal discussion, Bennett reiterated his support for merit pay for school teachers, suggested that the National Education Association's recent move to moderation was inspired more by politics than concern for education and said students should be forced to repeat grade levels in high school if they cannot meet strict standards.

On another topic, Bennett said he rejected the charge, leveled by critics of President Reagan, that federal budget cuts were the cause of a decline in black college enrollment over the last five years. "I will not accept the answer that we see declining numbers because of the Reagan administration," Bennett said. "Enrollment trends just don't follow the availability of federal funds."

Rather than point the finger at the administration, Bennett said, "My guess is that it has more to do with some sense that the payoff isn't there, that higher education isn't all it's cracked up to be."

Bennett said the problem may be exaggerated because the time period is too short to draw any firm conclusions from the statistics. He also said the educational reform movement that advocates stricter standards of performance for both students and teachers could serve to better prepare blacks for college.

"The numbers interest me less than what's going on in the classrooms," he said. "I'm interested in the entry point of the thing . . . . When the schools get sloppy and the standards start to decline, the students who get hurt are those who have the most to gain from education," particularly blacks.

Bennett said that, with budget issues nearing resolution on Capitol Hill, he hopes to turn his attention to pushing for his favorite three issues, which he has dubbed "The Three C's" for content, character and choice. Content refers to what is being taught in the schools, character to the values that content instills in students and choice is generally shorthand for tuition tax credit and voucher plans.