Members of Congress and American Jewish leaders praised President Reagan's commitment to Israel's security and rejection of an independent Palestinian state in his Middle East proposals last night, but some expressed fear that he is placing too great a burden on Israel.

Some Jewish organizations objected that Reagan's proposals undercut the Camp David accords and repeated their arguments that the moderate Arab nations, particularly Saudi Arabia and Jordan, must provide a tangible demonstration of their commitment to peace.

Claiborne Pell (D-R.I.), ranking minority member of the Senate Foreign Relations Committee, praised the proposals for their "ironclad commitment to Israel's security" and call for a freeze on further settlement of the West Bank. He said the speech expressed "noble goals with which Americans generally agree."

"My own feeling is he's much too stern with Israel with regard to their problems and the West Bank," said Clement J. Zablocki (D-Wis.), chairman of the House Foreign Affairs Committee.

"I think he's violating some of the Camp David agreement, and he's just stepping out a little too far without first giving the Israelis the opportunity to clear out of Beirut," said Rep. Benjamin S. Rosenthal (D-N.Y.), a member of the committee.

Sen. John W. Warner (R-Va.) praised the speech as "a courageous proposal which could establish a framework for a lasting peace. . . ." Sen. Richard G. Lugar (R-Ind.) called it "a comprehensive and courageous speech outlining a new Middle East initiative."

Thomas A. Dine, executive director of the American Israel Public Affairs Committee, also voiced serious reservations.

"We are pleased with the president's commitment to Israel's security . . . but we oppose any attempt to dictate the outcome before negotiations begin," Dine said. "This proposal undermines Camp David, which intentionally left the outcome open to negotiation."

"AIPAC . . . is pleased that the president has ruled out an independent Palestinian state, a threat both to Israel and Jordan," Dine said.

Sen. Charles McC. Mathias (R-Md.), a member of the Foreign Relations Committee, praised Reagan for defining the Middle East problem, which he said is the "first step to solving it."

"The president is accurate in observing that . . . there are two horns to the dilemma," Mathias said. "One is Israel's need for security and a sense of confidence; the other is the Palestinians' need for national expression."

Mathias said his committee has scheduled a meeting with Secretary of State George P. Shultz.

Robert Joseph, president of the National Association of Arab-Americans, praised the plan but added that negotiations should include the Palestine Liberation Organization as representative of the Palestinian people.

"We particularly appreciate as a positive feature the statement that the ultimate status of Jerusalem is negotiable and the call for a freeze on the existing number of Jewish settlements" on the West Bank, he said.

Representatives of almost all major Jewish organizations are to meet with Shultz this afternoon in a session that could do much to determine the future posture of American Jewry on the U.S. initiative outlined by Reagan.

The major theme of initial reaction by these organizations was welcome for Reagan's expressions of commitment for Israel's security and his calls on Jordan to enter the negotiating process.

But there was consistent criticism of Reagan for positions viewed as preempting the negotiating process outlined under the Camp David accords.

"The genius of Camp David was that the ultimate solution of the problems addressed in the accords was to be postponed for a five-year period," during which negotiations were to occur, said Hyman Bookbinder, longtime representative of the American Jewish Committee.

"For the U.S. now to say what it wants to see at the end of those negotiations seems to foreclose real, genuine, free negotiations," he said.

The speech had some clear positive points, Bookbinder said, referring specifically to Reagan's rejection of a Palestinian state, his affirmation of Israel's security and his appeals to Hussein and the Palestinians to join the negotiations.

Bookbinder was critical of Reagan's position on Jewish settlements in the West Bank, however, saying, "It would have been much better to have this come about as the result of negotiations. . . .

"So far, only Israel has shown a willingness to negotiate," said Kenneth J. Bialkin, national chairman of the Anti-Defamation League of B'nai B'rith. "So it is unrealistic to ask Israel to make pre-negotiation concessions until the Arab states have shown a willingness to accept the president's general principles."