Future changes in the $59 billion government-military payroll would be tied to local industry pay rates and fringe benefits under a salary "reform" plan that President Carter will send to Congress soon.

I Congress moves quickly, the proposal could be in operation to affect the October 1980 raise due nearly 500,000 federal and military personnel here.

Already the Bureau of Labor Statistics is developing "computer models" to allow it to catalogue and compare fringe benefits and salaries in 1,500 firms against salaries and benefits for white-collar civil servants.

The plan will be called TCC (Total Compensation Comparability). It would replace the present system that sets federal salaries on a national basis by comparing government pay rates to selected private industry salaries. The current system does not include fringe benefits in its comparisons, nor does it allow for local adjustments.

One part of the Cater TCC plan would link hundreds of thousands of federal jobs geographically to hometown industry pay levels. If followed strictly it would mean that government clerical pay, now the same everywhere, could vary as much as $150 a week from city to city.

Under the area wage concept which the government now uses for its half-million blue-collar workers, many federal jobs in cities like Boston, Detroit and Washington would pay more than the same work performed in San Antonio, Jackson, Miss., and Little Rock, Ark.

Although the methods for comparing fringe benefit values between government and industry have not been completely worked out, sources say such a system could be in partial operation in time to have an impact on the October 1980 pay raise due federal-military personnel.

Government white-collar civilians and the military get annual wage adjustments each October. They are based on data collected by the Labor Department's BLS, and are supposed to result in raises that, on a national average, will keep the federal work force on par with industry.

Those raises are subject to revision by the president (with consent of Congress) and both the 1978 and 1979 raises were or will be 5.5 percent, despite government data showing government employes were due more under strict comparability. Carter made the decision to hold down raises as part of his anti-inflation program.

The problem of assigning values to fringe benefits and methods of comparison are complex and open to dispute. Much depends on who is doing the figuring. The civilian federal payroll is about $39 billion each year, and each 1 percent pay raise for government and military personnel costs $500 million.

Depending on how they figure it, federal officials say that the value of government worker fringe benefits can be as low as 16 percent, or as high as 30 percent of the payroll. Obviously the methodology adopted - plus the area wage concept - could mean millions of dollars more, or less, for government workers with each pay adjustment.

Administration officials hint - but do not promise - that President Carter would be less likely to shave future federal pay raises if his TCC plan is adopted. They argue, correctly, that many people mistrust the federal pay-setting system, and hardly anyone understands it.

If Congress, the president and public could be convinced that federal pay-fixing machinery (driven, after all by federal workers) more accurately reflected the private job market, aides say the president would be less likely to use it as the spearhead for anti-inflation programs.

The plan will soon be handed over to Congress for its advice and consent. But the Carter administration may be making a tactical mistake with some key members.

Word is out that Rep. Gladys N. Spellman (D-Md.) is being bypassed by administration officials who are test-flying the TCC model before other subcommittee leaders of the Post Office-Civil Service Committee.

Spellman's subcommittee normally is the first channel that the Carter pay plan would take in the House. The chairman of the full committee, Rep. James M. Hanley (D-N.Y.), is close to the administration, but also anxious to establish his independence - and control - over handling the legislative end of federal pay and fringe benefit proposals.

Insiders believe Hanley may diplomatically recommend that Carter messengers stop by Spellman's office to give her the pay plan and smoke a peace pipe before they send the bill to Capitol Hill. Hell hath no fury like a chairperson scorned, as the Carter folks ought to know by now.