The republican Party has set aside almost a quarter of[WORD ILLEGIBLE] record $20.7 million budget for the year to provide political help to President Reagan, including $2 million for an advertising campaign to boost his economic program, according to GOP Chairman Richard Richards.

However, Richards says it is doubtful that the ad campaign will be necessary, so the money for it likely will be set aside for use during the critical 1982 election campaigns.

Reagan is expected to use most of the $2 million the Republican National Committee has budgeted for White House support and political travel and the $1 million set aside for polling.

The figures are included in a budget that indicates the GOP will out-spend the financially hard-pressed Democrats by more than 4 to 1 this year. Republcian expect to raise $28.8 million -- almost $12 million more than their current total for a non-presidential election year.

The party expects to have $20.7 million left to spend after fund-raising costs, compared with $4.6 million for the Democrats.

This will enable the GOP to operate an ambitious program, one of the chief beneficiaries of which will be Decision Making Information, headed by Richard Wirthlin, Reagan's pollster in 1980.

DMI has been commissioned to do 12 to 16 national opinion polls during the year, as well as statewide polls, for $900,000. Wirthlin says the results will be used by the White House to measure Reagan's popularity, and by the RNC in assessing attitudes about the party.

In contrast, the firm headed by Pat Caddell, pollster to President Carter, received commissions totaling $1.3 million from 1977 through 1979 from the Democratic National Committee, according to a party spokesman.

Wirthlin's polling apparently will be far more sophisticated than anything previously undertaken by a political party. One element is to expand the political information system he used so successfully last fall to guide Reagan's strategy.

In it, current polling data is combined with information on a state's historic voting patterns and judgments on political trends to predict how voters will respond to issues and appeals.

Republicans are also getting an early jump on Democrats in 1982. The budget sets aside $3 million for congressional candidates next year. This will increase to $5 million if the ad campaign is dropped. The party has budgeted $1 million for redistricting efforts and $784,000 for state and local republican candidates this year.

For example, it has agreed to give $100,000 each to J. Marshall Coleman, the GOP gubernatorial candidate in Virginia, and Thomas H. Kean, the party nominee for governor in New Jersey. It has given $27,500 to GOP nominees in four special congressional elections this year.

The RNC currently has a full-time staff of about 280, down about 50 from the heart of the presidential campaign last year. It owns a headquarters building on Capitol Hill that houses a printing plant and television studio and from $750,000 to $1 million in computer hardware and $2 million in software.

This year it plans to spend $1.2 million publishing a monthly magazine, First Monday; a new semi-weekly magazine, Source; a scholarly journal, Commonsense, and various newsletters.

It has a political budget of $6.5 million that funds an extensive field staff, efforts aimed at ethnic groups, research on Democratic opponents and candidate training and recruitment drives.

The republicans also have more successful Senate and House campaign committees. In 1980, the GOP groups raised about $44 million; their Democratic counterparts, less than $13 million. It is not known precisely how much that contributed to the Democrats' loss of the presidency, 12 Senate seats and 33 House seats.

Although Democrats have stepped up their fund-raising efforts, their national committee still leads a hand-to-mouth existence. And when their House and Senate campaign committees rasised $1.5 million at a gala dinner last month, the first $200,000 went to repay a loan.

The RNC, relying largely on relatively small donations solicited by direct mail, has steadily built its annual budget from $4 million in 1969 to $6.5 million in 1974 to $17.5 million in 1979.