Senior government executives, managers and supervisors are expected to receive lower marks on their annual report cards than they did last year, because of an intensified "grade-tough" policy.

Most of the bosses who do the ratings have been told, informally or otherwise, not to give "outstanding" or "exceeds fully successful" ratings on the reports due next month just because they want to keep everybody happy. Some have been told that if they hand out too many top marks, their own performance ratings will suffer.

The August-September rating period is critical to the government's 120,000 mid- and top-level career managers and executives whose salaries range from $39,930 to $63,000. Nearly half the folks being rated live and work in the Washington area.

Unlike rank-and-file white collar workers who get automatic pay adjustments, many people in the upper reaches of the civil service are under a performance-based merit pay system. Their pay raises are largely determined by their annual performance appraisal.

Slightly more than half the money for pay raises for executives and managers comes from a special pool within each agency. For that reason, agencies that give top ratings to a large number of executives have to give out smaller percentage increases than agencies that reserve top marks for a smaller number of people.

Pushed by the Office of Personnel Management, several departments and agencies have told top managers to give fewer top marks.

"We have got to convince people that a rating of 'fully successful' equivalent to a "C" in a five-tier grading system is all right," an OPM official said yesterday.

OPM issued the same call last year but many agencies ignored it because OPM had no way of tracking their grading patterns. This year it will keep a closer eye on performance appraisals.

One place that is expecting more "realistic" performance appraisals this year is the Labor Department.

Just before last year's grading period, Secretary Raymond Donovan told his top managers that too many people were getting top marks. In a memo to the executive staff, Donovan said, " . . . The major problem we face is to reduce the very high percentage of ratings at the 'highly effective' and 'outstanding' levels.

"Unless a more meaningful distribution of ratings is achieved the appraisal results will not be a useful measure for pay decisions . . . ," the memo said.

Donovan said that if most people are rated better than "fully successful," something is wrong. Managers who "demonstrate continued inability to properly evaluate their staff" should get extra training in appraising staff, he stated; further, "this shortcoming must be reflected in their own performance appraisals."

Personnel directors in several other agencies say the grade-tough word is out. "We did it in my own office last year to set an example," one personnel director said. "I can tell you there were some long faces. Everybody here is mad at me."

If things go according to plan, he predicted "that everybody is going to be made at everybody . . . once the performance ratings are out for fiscal year 1983."