There are now nearly 200 former admirals and generals in government, each of whose combined pay and pension exceeds the $66,000 yearly salary of the Cabinet officers who hired them, according to a new congressional study.

Chairman Robert N. C. Nix (D-Pa.) says the number of high-ranking officiers who take federal jobs jumped 26 per cent in the past three years. Thanks to a system that gives them three raisers a year - a total of 16.1 per cent in 1977 - at least 40 of the retirees now get more from the government that Vice President Mondale, who is paid $75,000.

Nix's Post Office-Civil Service Committee has just completed a study of the impact of military retirees on the civilian arm of the government. Among other things it shows that:

Fifty-five percent of the 141,817 military retirees employed by the government work in Defense Department jobs, some of them in areas in which they once held high-level or commond rank.

The U.S. Postal Service and Veterans Administration rank second and third as major employers of military retirees in government.

Washington has more military retirees, and more high-ranking retirees in federal civilian jobs, than any other area of the country. San Diego and Norfolk are next, both with extremely high concentrations of ex-Navyofficers on the federal payroll.

Despite laws designed to offset the pensions of retired "regular" officers who take civil service jobs, fewer than 4 per cent of the retirees actually take pension cuts because they have been granted special waivers of the law.

Officers retiring for nondisability reasons had reached an average age of 46, with 25 years in military service, when they took federal civilian jobs. Enlisted retirees averages 22 years in the military, and were 42 when they first were hired by the government.

The number of military retires working for the Defense Department jumped 19,383, or more than 30 percent, from 1972 to 1975.

Chairman Nix, who also heads the House Investigators Subcommittee, said the government now spends more than $300 million making dual payments to military retirees. He warned that the costs would jump in the future as officers "receiving excessive amounts from the government" get cost-of-living raises as military retirees, and regular annual pay raises as civilain civil servants.

Because they are entitled to raises both as military retirees and as active federal workers, the ex-military careerists last year got combined pay and pension increases of 16.1 percent.

Regular civil servants get a catch-up-with-industry pay raise each October. In 1977 that raise was 7 percent. Retired federal and military personnel get cost-of-living raises that, in 1977, amounted to 9.1 percent.

In addition, they just got another cost-of-livng adjustment this month of 2.4 percent. They are due a second inflation-catch-up increase that will be effective in September, and payable in October, the same month when they will be getting another raise as civilian workers.

Nix believes an overhaul of the dual compensation system - protecting pay and pension of retired enlisted peronnel - must be made. He has indicated that his committee would begin to push for it later this year.

Federal Military Pay Raise: Administration officials indicated yesterday that they will continue to recommend a mandatory ceiling on federal-military pay raises this year, despite opposition from government worker unions.

White House officials told union leaders at a Civil Service Commission session that a gap of between 5 per cent and 5.5 percent is necessary to persuade the private sector to hold down wages and prices this year. They conceded that federal workers have been among the chief victims of inflation, but argued that the "voluntary" program the president will push for the private sector must be kicked off by mandatory controls for the federal and military establishment.

National Secretaries Week: April 24 through 28 has been designated National Secretaries Week, much to the delight of local florists and restaurant managers.

Secretarial Job: National Science Foundation has a Grade 5 or 6 opening for a secretary-typist to work on research proposals and deal with scientists around the country. Call Dr. Guth at 634-1624.

Accounting Technicians: General Accounting Office has openings at the GS 4 or 5 level for the technicinas, and for voucher examiners. Send Form 171 to the personnel office, Room 7536, 441 G St. NW. 20548.

Legal Secretaries: The new Office of Rail Public Counsel is recruiting secretaries with legal-litigation backgrounds. Call 254-7803 for details.