President Carter opened two days of talks with King Hussein of Jordan on a cautious note yesterday, declaring "it would be a mistake to be too optimistic" about the chances for major strides this year toward an Arab-Israeli peace.

In the latest in a series of intensive meetings with Middle Eastern leaders, Carter appeared to be tailoring his remarks to his guest's well-advertised caution. Hussein, in a television interview broadcast as he arrived here, said he is "far less optimistic" than he had been earlier this year "because it doesn't appear to me that Israel is in a position to contribute all that much towards the establishment of peace."

Hussein has expressed concern that soaring optimism, if abruptly deflated, could lead to an "explosion" that could endanger moderate leaders like himself. A few days ago he told an interviewer for the French newspaper Le Monde that "those who are telling Arab opinion that peace could be established in 1977 are playing with fire."

In a toast at a White House "working dinner" last night at the end of his day of conferences, Hussein sounded a bit more optimistic. Despite his feelings of caution, he told Carter, "I have after meeting you and our friends felt more encouraged and hopeful than I have for a long time."

A White House statement issued following a 75-minute Carter-Hussein meeting said the two agreed "that the time is right for a major effort looking toward reconvening the Geneva conference in the second half of 1977." The statement said Carter and Hussein discussed "various ideas" about solving the problem of Palestinian representation, which is the procedural roadblock standing in the way of such a conference.

Hussein has the largest stake of any Arab leader in the settlement of the Palestinian problem. Some 70 per cent of Jordan's 2.8 million people are Palestinian Arabs, including 750,000 who are living under Israeli occupation in Jerusalem and the West Bank of the Jordan River. The future of the Israeli-held territory is crucial to a comprehensive settlement and is also crucial to Jordan's security and stability as well as Hussein's continued rule.

White House officials said there was no discussion during yesterday's initial meeting of the Central Intelligence Agency payments to Hussein that were disclosed by The Washington Post Feb. 18. In the Le Monde interview, Hussein indicated that Jordan had received funds for its counterespionage operations from U.S. intelligence, but declared it was "an attempt at character assassination" to suggest the money went into his own pocket rather than the public purse.

"It is true that, by tradition, the checks were printed in my name," Hussein was quoted as saying. Hussein told the French paper that the CIA controversy belongs to the past, because he received satisfactory messages from Carter and the U.S. government.

Hussein met late yesterday with Secretary of Defense Harold Brown in what U.S. officials called a general review of diplomatic and military questions, Jordan is purchasing F-5E warplanes, tanks, howitzers and other equipment with U.S. military aid. It is acquiring Hawk air defense missiles in a commercial deal paid for by Saudi Arabia.

Sources said Hussein made no major arms requests during the meeting with Brown.

While Hussein was conferring with top U.S. officials, the Israeli ambassador to Washington, Simcha Dinitz, made a speech to a group of American Jews that seemed to underscore the difficulties of a peace agreement.

Dinitz told the American Israel Public Affairs Committee, a lobby group that backs Israel, that "an optimum peace" containing dramatic changes in the Middle Eastern situation is necessary for there to be "any movement" diplomatically on the part of Israel.

He also spoke at length of Israel's demand for "defensible borders," defining them as borders that would provide Israel with "a deterrent" against any Arab military action and "easier victory" in case a new conflict should break out.