The massive immigration-reform bill, revived in a behind-the-scenes compromise last week, became moribund again yesterday when House conferees balked at a cost-containment provision demanded by the White House.

A House-Senate conference on the controversial measure disbanded without scheduling further meetings after House conferees voted, 15 to 13, against a $1 billion cap on annual federal reimbursements to states for welfare and other costs associated with legalizing millions of illegal aliens.

Sen. Alan K. Simpson (R-Wyo.), the bill's chief Senate sponsor, held out the possibility of further action on the measure, but other conferees said they were less confident that anything can be done before Congress adjourns for the year, probably in the next few days.

"They say it's not over until the fat lady sings. Well, she just came on stage," said Rep. Daniel E. Lungren (R-Calif.), a stong supporter of the measure.

"I wouldn't want to characterize it as dead, but it doesn't have much life," said House Judiciary Committee Chairman Peter W. Rodino Jr. (D-N.J.), who has been chairing the conference.

Administration officials have said they believe that the bill could cost $12 billion over five or six years. It allows aliens given amnesty to qualify for Supplemental Security Income for the indigent aged, blind and disabled, emergency medical care, child nutrition and school lunch programs as well as several smaller welfare and education and training programs.

President Reagan has expressed serious concern about the costs and indicated that he would veto the measure if the $1 billion cap is not written into it.

The conferees had agreed to include in their report support for the cap, but that would not have the force of law and could be exceeded.

The conference was considering the funds cap as part of a carefully arranged compromise to which key conferees agreed last week. It was designed to resolve a long stalemate over an anti-discrimination provision in the bill.

Yesterday, the anti-discrimination compromise was approved easily, but the funds cap lost after conferees from such states with large illegal immigrant populations as Florida, California and Texas said it would impose an unfair burden on their taxpayers.

During debate on the cap, Simpson said he could not go along with the House conferees' action because Reagan would just veto the bill if it didn't contain the cap. Afterward, he said it would be a "bum rap . . . to lay this at the feet of the president because the Senate is the one that's not agreeing."

However, Rep. Barney Frank (D-Mass.) said, "We could work this out among ourselves, but we come to the end and we are told . . . that the president of the United States has decided he will shut the whole thing down if he doesn't get his $1 billion cap.