Secretary of State Cyrus Vance learned yesterday that a two-thirds majority of the Senate Foreign Relations Committee opposes the administration's proposed sale of 60 F-15 fighter-bombers to Saudi Arabia, at least at this time.

At a closed-door meeting of the committee, Vance received two letters signed by 10 senators on the 15-member committee urging him not to forward a formal notification of the proposed F-15 sale to the Congress now. A notification would be the first step in the legislative process that eventually gives Congress an opportunity to veto a proposed arms sale.

Vance said after the meeting the administration would take into account the senators' view in deciding its next move.

Saudi Arabia has made this sale a major issue by interpreting it as a symbol of Saudi-American relations. In effect, the Saudi government has told the United States to prove that Saudi Arabia is an important American ally by selling it the sophisticated airplanes.

The Carter administration has decided it must go through with the sale, but friends of Israel in Congress and other opponents of the plan threaten to block it.

Sen. Frank Church (D-Idaho), the ranking Democratic member of the Foreign Relations Committee and the author of one of the letters on the F-15 sale, told reporters Vance said he had not made up his mind yet how to proceed.

Church said the issue may come up today at a meeting of the National Security Council. He said he thought the administration should "review" all plans to sell any arms in the Middle East while peace negotiations are going on. Supplying new arms now would suggest the United States has "no confidence in the peace negotiations," Church said.

Ezer Weizman, Israel's defense minister, this week postponed a visit to Washington scheduled to begin today during which he was expected to press for new arms sales to Israel, including the same F-15 fighter-bombers.