THE SENATE Labor and Human Resources Committee has proposed a new condition for federal aid to college students: acceptable grades. The provision was included in a bill the committee reported out last week extending the full array of aid to higher education for another five years. The impulse is understandable: the programs now cost about $9 billion a year, and the senators don't want it said they are paying people to goof off. The standard finally set was also pretty low: not a C average at the end of sophomore year, as first proposed, but merely a record "consistent with the requirements for graduation." It is still the wrong thing to do. The government should not become a grade policeman. Grades are between a student and school and best left that way.

Otherwise this is an excellent bill. President Reagan proposed in his budget to cut the main forms of aid by 40 percent in the next five years, the wrong way to treat a major equalizing force in the society. The committee voted unanimously instead to keep the programs pretty much as they are. The House passed similar legislation last year; perhaps this is one subject on which the 99th Congress will be able to act in an orderly way.

There are two main programs, one grant, one loan. Grants haven't kept pace with costs in recent years, and low-income students have had to rely more and more on loans. They graduate heavily in debt. The committee bill would raise the maximum grant from the current $2,100 to $3,200 by 1991 (the House bill would go to $3,100 in the same period) to redress this.

The committee also voted to bar grants from the main program to students from families with incomes above $30,000 a year. There is no such limit now. The colleges say an income cap shuts out large families made needy by the fact they have several children to educate at once. But the president has proposed a cap, the program is regularly denounced for helping the rich as well as poor, and the senators decided this was an issue on which it was easiest to yield.

The bill would also tighten the definition of an independent student (one who doesn't live with his parents, who therefore can't be dunned to help pay for his education), lower the rate of return of the banks on student loans and impose a greater penalty than now on states in which large numbers of students default. The theory is this will give the states an interest in helping the federal government collect.

Except on the grades provision, an A. On that, a D. But the Senate or conferees can fix it.