The new student-aid program proposed by President Reagan presents a sharp break from the philosophy of the recent past.

Ever since the mid-1970s, large numbers of middle-class families have been getting government help with their college bills. Pell Grants--the basic student-grant program--are available to families making as much as $26,000 (although at that income level, the awards are generally small). Government-subsidized student loans were made available to all students, regardless of income.

Student aid did not start out that way. Originally it was meant to equalize economic opportunity, by helping students from poor families get a higher education.

But as time passed, middle-class families started to get angry. They saw poor children going to school on scholarships, while their own children struggled to meet the bills. And whenever the middle class gets sore, Congress hustles to kiss the place that hurts. Student-aid programs were promptly expanded.

President Reagan is turning the idea of equity around. He thinks that it isn't fair for middle-class students to get aid at the taxpayers' expense. He believes that the burden of paying for higher education should fall mainly on parents and students, not on society as a whole.

Under his proposals, most middle-income families would no longer be eligible for Pell Grants. Grants to low-income students would continue, but their size would shrink. By reducing grants in the face of rising college costs, the new program assures more financial hardship for low-income students, too.

There are several other guiding ideas behind the proposed student-aid reductions.

The administration sees no reason to make it easier for a student to go to a high-cost school, when lower-cost schools are open to him. Education Department officials also believe that a student can make up the money he loses in student aid by working part-time. (The economic recovery projected for 1983-84 is expected to provide more jobs for young people.)

In the new scheme of things, graduate students are considered capable of working and saving enough money to pay for their own educations, without help.

How many of President Reagan's cuts will actually pass is open to question. He might get only token changes in this sensitive election year. But he'll be back the next year and the year after that, to try again. It's a trend that no student or parent can afford to ignore.

Here is what's proposed for the 1982-83 school year:

1. Students will lose their eligibility for the Pell Grant program if their adjusted family incomes reach roughly $15,000 to $18,000, compared with a top of about $26,000 today. At the $15,000 income level, your award is likely to be only $100. The lowest income students may get as much as $1,600 depending on where they go to school.

2. Students with incomes as low as $10,000 might find themselves ineligible for Pell Grants if they attend a very low-cost school. Due to a change in the formula for computing need, it could be determined that families in this income range can afford to pay for a low-cost school themselves.

3. No money will be provided for supplemental education opportunity grants, now given to low-income students through college financial-aid offices.

4. State student incentive grants will be eliminated. This money helped finance state student-aid programs; the administration believes that states can keep up these programs without help.

5. Work-study programs, which finance jobs for college students, will be cut by about 27 percent.

6. No one will get a government-guaranteed student loan without first passing a test of financial need. Eligible undergraduates may get 9 percent loans for their first two years of college; after that, they'll be charged market interest rates. The upfront fee for getting a student loan will rise from 5 percent to 10 percent, plus another 1 percent charged by many states.

7. National direct student loans, for low-income students, will receive no new money. But schools can still make new loans as old ones are repaid.