The legislation approved by Congress yesterday will reduce the projected $180 billion federal deficit in the fiscal year ending Sept. 30, 1988, by $33.3 billion, more than the $30.2 billion required by the Nov. 20 budget accord between congressional leaders and the Reagan administration.

The first of the two pieces of legislation is a $598 billion omnibus appropriations measure for fiscal 1988 that funds those government operations dependent on annual spending bills. Since Oct. 1, the beginning of the fiscal year, the government has been operating under four short-term continuing resolutions that funded agencies at last year's levels.

The second deficit-reduction bill is a package of tax increases, sales of federal assets and cuts in such nonappropriated programs as Medicaid, Medicare and farm subsidies. It would reduce the federal deficit by $17.6 billion in 1988.The $598 billion spending bill:

Provides $8.1 million in nonlethal funding for the Nicaraguan contra rebels through the end of February and allows shipment of previously authorized military aid until Jan. 12. If the Central American peace process collapses in mid-January, and the president certifies the failure is the fault of the Marxist Sandinista government, that residual military aid can resume between Jan. 19 and Feb. 29. It also guarantees House and Senate votes on Feb. 3 and 4 on any new Reagan administration request for further military aid. If the president loses that vote, he loses the chance for a second guaranteed vote. If he wins, he gets one final guaranteed vote on a second new request for military aid between July 1 and Sept. 30.

Cuts spending for government programs by $15.6 billion, including $5 billion in military programs and $2.6 billion in domestic discretionary accounts covering such items as education and law enforcement. The bill includes $3.9 billion for the Strategic Defense Initiative compared with the president's request of $5.7 billion.

Allows the administration to sell up to 70 Stinger antiaircraft missiles to the Persian Gulf sheikdom of Bahrain, but that nation would have to return any unused missiles within 18 months.

Permits the administration to resume sending $480 million in foreign aid to Pakistan if it waives current law barring aid to nations that have a nuclear weapons capability but do not submit to international inspection.

Gives most federal workers a 2 percent pay increase, except members of Congress, federal judges and senior executives.

Delays by eight months to Aug. 31 the imposition of financial penalties against metropolitan areas that fail to meet pollution standards for ozone and carbon monoxide under the Clean Air Act.

Provides $905 million for AIDS research, nearly double last year's amount.

Clears the way for 20 states to increase the speed limit to 65 mph on rural four-lane highways for four years. Currently states can raise the limit only on rural interstate highways.

The tax portion of the "reconciliation" package would raise revenue through a variety of increases on corporations and well-off individuals.The tax portion's provisions:

Extend the 3 percent tax on telephone service, which otherwise would have expired at the end of this year.

Limit the deduction for interest on a home mortgage to loans of $1 million or less, for up to two residences.

Limit the deduction for other loans using a home as security to amounts of $100,000.

Allow individuals who pay taxes on an estimated basis to pay only 80 percent of their ultimate bill in advance rather than 90 percent as current law requires.

Freeze the top rate on estate and gift taxes at the current 55 percent for five years, rather than allowing it to fall to 50 percent next year.

Require inactive-duty military reservists, some agricultural workers and children who work for their parents to pay Social Security taxes.

Deny the tax credit for child care for the expenses of sending a child to overnight camp.

Extend a 0.2 percent surtax on the unemployment-insurance tax paid by employers for three years.

Close an estate-tax loophole opened by last year's tax-revision law that had provided advantages for investing in employe stock ownership plans.

Accelerate the collection of estimated taxes paid by corporations.

Increase the base contributions companies make to the Pension Benefit Guaranty Corp. from $8.50 per employe to $16, with additional contributions of up to $34 possible for companies with underfunded pension plans.

Raise the railroad-retirement tax and permit the general fund to subsidize the railroad fund for one year.

Impose a 50 percent tax on stock gains by corporate "raiders" incurred when they try to take over a company.

Require defense and construction contractors to pay taxes on at least 70 percent of their income each year rather than the current 40 percent.

Deny use of the foreign tax credit to income American companies earn on operations in South Africa.The spending portion of the reconciliation bill:

Cuts the growth of Medicare, the health-insurance program for the elderly and disabled, by $2.1 billion in 1988 and $3.6 billion in 1989. About $550 million of the 1988 savings would come from extending the automatic spending cuts through next April for most Medicare programs.

Increases spending for Medicaid, the health program for lower-income Americans, by $44 million in 1988 and $633 million over three years.

Permits retiring federal workers to take only 60 percent of their benefits in the year they retire, rather than the entire lump sum that they are now allowed. They could take their 40 percent the following year. The provision covers workers retiring in fiscal 1988 and 1989.

Postpones some future U.S. Postal Service construction and requires the service to compensate the general fund for some health-benefit costs for retirees. The Postal Service would not be allowed to raise rates to cover the higher costs.

Orders the Energy Department to select Yucca Mountain, Nev., as the site of the nation's first and only high-level nuclear waste dump.

Reduces agricultural target prices and loan rates -- the price below which farmers can forfeit their crops and keep their government loans -- for major commodities.