The Senate, voting 70 to 18, last night followed the House in approving funds to assure that the food stamp program will not be suspended next month. Because the Senate voted $500 million more than the House, a House-Senate conference must resolve the difference.

But the fact that both bodies have voted the funds should be enough to meet the administration's deadline that the money be made available by today to keep the program in operation beyond May 31.

Two hurdles had to be cleared before the Senate could vote on the $3 billion reccommended by its Appropriation Committee to carry the program through the end of the fiscal year Sept. 30.

First, the Senate approved, 65 to 25, a House-Senate conference report on a bill that authorized the increased spending.

Next, the Senate voted to waiver from a provision in the Congressional Budget Act that forbids consideration of legislation that would break through the spending ceiling imposed by this year's budget resolution. Both House and Senate have voted to raise the ceiling to make room for the food stamp appropriation as part of the budget resolution recently passed by both bodies. But the resolution is still in conference and has not taken effect.

Sen. Ernest F. Hollings (D-S.C.) and Sen. Henry L. Bellmon (R-Okla.), chairman and ranking Republican on the Senate Budget Committee, both recommended waiving the budget act because the food stamp program would otherwise face what Bellmon called an "intollerable situation."

Secretary of Agriculture Bob Bergland has said that if the needed extra funds have not cleared Congress by today he must order the food stamp program suspended June 1. Twenty-one million people depend on the program to help buy food.

Some conservatives who contend that the program is growing too big and is full of fraud and abuse tried to slow down the drive to approve the funds last night. Sen. James A. McClure (R-Idaho) said the May 15 deadline was an arbitrary one, picked to scare Congress into voting the funds without time for full consideration. There is enough money left to continue the program into June, McClure said.

The House approved $2.5 billion in extra food stamp funds, so there may have to be some last-minute dickering today on the final figure.