White collar federal workers once thought heaven on earth would be pay equality with the private sector. Now many would be happy to settle for equal treatment with other federal workers, if anybody could figure out what that meant.

The government's $69 billion pay picture is especially confusing this year. It suffers from different systems, different laws and different applications of the administration's wage-price guidelines which are voluntary for some people but mandatory for others.

The way things stand, white collar civilians and military people will be lucky to get 5.5 percent this October. Postal workers say they want 14 percent beginning next month or they might strike. Some blue collar workers have already received 8.2 percent while colleagues here and elsewhere doing the same jobs may get much less. Federal firefighters just had a potential 15 percent boost cut from under them. And government executives probably won't get any pay raise this year. Example:

President Carter has imposed his "voluntary" wage-price controls only on federal white collar workers this year. This means they will get no more than 5.5 percent this fall, althouh data indicates a catch-up-with-industry raise of around 7 percent due them.

Postal union leaders are asking for around 14 percent for the 650,000 workers covered by their about-to-expire contracts with the U.S. Postal Service. The White House has no control over their wages, and the unions have warned of wildcat strikes - they have happened before - unless members get what they want.

That is a $1,100 raise this July and another $865 next year. It would be in a two-year contract which also would guarantee quarterly cost of living retirement benefits eventually.

The White House, caught in a cost-vs.-strike bind, is looking for a diplomatic way to let the postal unions have as large a raise as possible without making the federal wage-price guidelines a complete farce.

Federal executive making $47,500 would not get any pay raise this year under legislation Congress will clear. It is part of an effort to go along with the administration's wage "restraints" for all executives, but primarily designed to let Congress - which took a $12,900 raise for each member last year - sit out any salary increases in election-year 1978.

Blue colar federal workers who get pay increases according to local rates paid in private industry would get very unequal treatment this year. Congress is working on language that would slap a 5.5 percent lid on upcoming blue collar (wage board) salaries. But nearly half the blue collar workers already have received pay increases that, riding the industry average, have worked out to around 8.2 percent. If Congress approves the blue collar pay freeze, it would hit Washington area federal blue collar employes who get their catch-up-with-industry increases in October.

Federal firefighters were denied what would have been a 15 percent to 30 percent pay raise when President Carter vetoed legislation to shorten their workweek. Carter said the bill was "inflationary" because it would force the government - mainly Defense agencies - to hire 4,600 new firefighters, at a cost of $46 million a year, if the workweek were cut from 72 to 52 hours.

At the moment, it looks as if the heavily unionized postal workers will make the best 1978 wage gains of any federal workers. And to do it, they may have to risk a strike.