The Senate scrapped a Judiciary Committee report on Benjamin R. Civiletti's nomination as deputy attorney general yesterday to head off a floor fight over Republican objections to its conclusions.

The maneuver, agreed to by Sen. James O. Eastland (D-Miss.), the committee chairman, clears the way for a vote Tuesday on the long-stalled Civiletti nomination.

Sens. Strom Thurmond (R-S.C.) and Malcolm Wallop (R-Wyo.) were prepared to challenge the report because it stated flatly that there had been no Carter administration "cover-up" involved in the firing of Philadelphia U.S. Attorney David W. Marston.

Marston became a national celebrity - and more recently a candidate for governor of Pennsylvania - when it was disclosed in January that Rep. Joshua Eilberg (D-Pa.) had called President Carter last November urging the prosecutor's dismissal.

Marston claimed Eilberg was under investigation by his office at the time. But Justice Department officials and the committee report contended there was no investigation under way at the time. Wallop and Thurmond disputed that finding.

Though Civiletti had little to do with the Marston dismissal, Republican committee members used his hearings to investigate the matter themselves. They were upset when the report written by a single Staff members, was issued without the knowledge or approval of any committee members.

An aide to Eastland said yesterday that the committee chairman agreed to drop the report in hopes of speeding a vote on the Civiletti nomination.

The agreement to drop the report didn't mean Eastland no longer backed its conclusion, the aide said.

Wallop said that all 38 Republican senators were prepared to back a motion to recommit the nomination until the report was withdrawn if Eastland hadn't agree to do the same without a roll-call vote.

Wallop challenged the findings of the newly deceased report on the floor yesterday, he said, because report on the floor yesterday, he said, because "it is wandering around, through with no status, and it's necessary to answer those incorrect conclusions."