If the Senate Appropriations Committee has its way, the off-again, on-again destiny of the new military medical university at Bethesda will be on-again.

President Carter, submitting his amended federal budget to Congress last month, omitted funds for the Uniformed Services University of the Health Sciences. The Pentagon announced plans to shut it down.

The school was created to train doctors for the armed services. Two buildings to house it are being built on the grounds of the Bethesda Naval Hospital. The first 32 students are being trained in temporary quarters.

The House, in passing a supplemental appropriation bill recently, did not include funds for the school. But last Thursday, the Senate Appropriations Committee voted 17 to 4 to grant the school nearly $12.5 million to keep operating until the fall of 1978.

That action is subject to approval by both the full Senate, which will consider the bill on Wednesday, and the House.

The move to provide the funds was led by Sen. J. Bennett Johnson (D-La). Creation of the school was the dream of another Louisiana law-maker, Rep. F. Edward Hebert, who until his recent retirement from Congress was chairman of the House Armed Services Committee.

Johnston arfued that a vote on funding would clear any uncertainty on the school's future.

"Such uncertainty is unfair to faculty and students presently at the school," declared the Appropriations Committee's formal report, which was filed yesterday with the full Senate.

"Moreover, further delay in resolving the issue will make it impossible for those applications already accepted for admission to plan for the fall semester," the report said.

Hebert and other supporters of the school contended it is needed to produce doctors willing to make a career in military medicine. Critics have asserted that doctors can be trained more cheaply at existing medical schools.