The Democratic Party rules commission moved tonight toward a compromise change that would shorten the 1980 presidential primary season and make it somewhat tougher for spinter candidates to win delegates.

The compromise, approved by White House representatives, appeared likely to solve the two major issues confronting the party panel recommending changes in the 1980 delegate-selection procedures.

Under its terms, all primaries, causes and conventions to pick national convention delegates would have to be held between the second Tuesday in March and the first Tuesday in June.

In the first four weeks of that period, any candidate receiving at least 15 per cent of the primary, caucus or convention or convention vote would be entitled to a proportional share of the delegates.

In the second four weeks, the floor would rise to 20 per cent, and in the last four weeks to 25 per cent.

State laws that conflicted with the new party rules would have to changed.

Shortening the delegation-selection seasons to 12 weeks is designed to slow or reverse the proliferation of primaries, which totaled 31 last year. It also is aimed at halting the competition of states for the prestige of holding the first caucus and primary.

In 1976, Iowa held the first caucus on Jan. 19 and New Hampshire moved its primary up to Feb. 24 in order to maintain its first-in-the-nation tradition.

President Carter's representatives on the commission pushed to raise the floor for winning a share of a state's delegates for the 1976 level of 15 per cent to 25 per cent.They said that change would reduce the danger of divisiveness arising from single-issue, dissident candidates. But others saw it as a move to choke off possible opposition to Carter in 1980 and objected.

The compromise keeps it relatively easy for splinter candidates to gain a share of the delegates in early primaries or caucuses, but it helps the leading candidate increase his delegate haul in later contests.

If approved here by the 59-member commission headed by Michigan Democratic chairman Morley Winograd, the new rules would have to be ratified by the Democratic National Committee.