House Democratic leaders put off action yesterday on a compromise $302.5 billion defense bill worked out last week by House and Senate conferees, after Democratic lawmakers angrily denounced the measure, its price tag and House Armed Services Committee Chairman Les Aspin (D-Wis.).

The decision to postpone a vote on the fiscal 1986 defense authorization, probably until September, came after a stormy caucus of House Democrats called at the request of House liberals who charged that the agreement was a "sell-out" to the Republican-controlled Senate.

The Senate voted, 94 to 5, to approve the conference agreement yesterday. The House originally was scheduled to vote on the package today.

Lawmakers described the caucus as unusually personal, with a number of Democrats accusing Aspin and the House conferees of undercutting the Democratic-controlled House by giving in to the Senate's higher defense spending figure.

The $302.5 billion figure is $10 billion more than the House approved in its defense authorization and in its budget resolution that sets spending limits for next year. With budget negotiations stalled, House Democrats have been voting to stay within the limits of its budget resolution on related legislation.

"The amount of negative feeling about the defense bill is amazing," said Rep. Charles E. Schumer (D-N.Y.). "The main reason is the number. We just cut $1 billion out of public housing for the poorest of the poor and now we're going to add $10 billion for this? Is this what Democrats stand for?"

Aspin said the conferees had not tried to undercut House budget negotiators. Instead, he said, they were trying to give more room in case they needed to move to higher defense spending to reach budget agreement with the Senate.

Aspin defended the conference agreement yesterday, saying the House had won some significant concessions from the Senate. He said that most of those complaining about the agreement had voted against the House bill as well.

Of the stormy caucus he said, "I would like to move the Democratic caucus to the right on defense issues and the House Armed Services Committee to the left, and it's going to be painful. Sometimes the liberals are going to be unhappy and sometimes the conservatives are going to be unhappy."

Part of the anger aimed at Aspin grew out of the circumstances that brought him the chairmanship. Last January, the Democrats ousted the aging Armed Services incumbent, Rep. Melvin Price (D-Ill.), then jumped over several other senior Democrats on the committee and elected Aspin as chairman.

Democrats dumped Price in part because they believed he and the committee were too conservative for the party and too often caved in to the Senate on defense issues. Aspin campaigned for the chairmanship promising to unify the party by fashioning a Democratic posture on defense that was more skeptical of the Pentagon without making the Democrats appear antidefense.

It was not clear whether Aspin could get a majority of his House Democrats to support the conference agreement.

Rep. Les AuCoin (D-Ore.) said, "People were angry because no one can tell where Reaganism ends and a distinctive Democratic doctrine begins. Aspin told the caucus in January that this year was going to be a time when a Democratic doctrine distinct from arms-at-any-cost would emerge."

Aspin acknowledged that "the bill does not entirely reflect the Democratic position. But you're dealing with the Senate. Don't judge the Democratic Party position on defense by what comes out of a conference with the Senate. Judge it by what comes out of the Democratic House."

Relations between Aspin and many Democratic liberals were strained earlier in the year over the MX missile. Several Democrats said Aspin won their support for the Armed Services chairmanship by promising to vote against further funding of the MX missile and complained when Aspin later became a point man for the Reagan adminstration in its fight to unlock money for the missile. Aspin has said he made no promises about the MX.