Senate Majority Leader Howard Baker (R-tenn.) and eight other U.S. senators held talks with King Khalid and other Saudi leaders today in the course of a Middle East tour that they consider crucial to the outcome of a Senate vote on new arms supplies to Saudi Arabia.

Baker and other senators expressed a strong desire to rate the Soviet threat as top priority in the Persian Gulf region. Secretary of State Alexander M. Haig Jr., who met Arab concern on that issue during his trip here last week, also listed gulf security as a high priority but played to his audience by saying it has "equal priority" with the need for progress in resolving the Arab-Israeli conflict.

Baker sought to make clear to the Saudi government that the secretary of state does not have the power to ensure that the Saudis get what they want. The Senate, which must approve such sales, has the final say, Baker told reporters here.

Some of the senators reportedly were privately concerned that Haig may have been overeager in his trip to minimize the Senate's capacity to bar an administration proposal to sell Saudi Arabia additional equipment for the F15 jet fighters it has already ordered, as well as sophisticated AWACS reconnaissance craft.

Baker said it is unsure which way the Senate will vote on the proposal, which Israel has vowed to oppose with an all-out lobbying effort.

[In Washington, Sen. Paul Laxalt, a Nevada Republican and confidant of President Reagan, said "there is deep division in the Senate on the Saudi sale" and added: "I would think that this is going to be hotly debated and I think at this point the majority of the Senate would probably be opposed to the sale to the Saudis of the whole package including the AWACS."]

Baker said he wants "to take the heat and drain some of the fever" out of the debate, which he said could become a repetition of previous "cataclysmic" congressional splits on Middle East arms deals such as the one that preceded approval of the original F15 sale to the Saudis and Israel.

He said he is sympathetic to a package to enhance Saudi Arabia's defense capacities, but believes the Reagan administration is prepared to show flexibility on the final shape and form of those proposals. Baker listed means of reducing Israeli and American fears such as joint manning of the AWACS by Saudis and Americans, sharing of intelligence gathered by the planes and limits on their use.