U.S. presidential envoy Zbigniew Brzezinski wound up his two-day trip to Saudi Arabia and Jordan today with no sign he has softened their opposition to the U.S.-engineered peace treaty about to be signed by Israel and Egypt.

Both nations issued statements that refrained from attacking Egypt or the United States on account of the treaty but nevertheless underlined the Arab contention that only a comprehensive Middle East settlement can guarantee security in this volatile region.

This was taken as a signal that neither the Saudi leadership nor Jordan's King Hussein will back the Egyptian-Israeli accord, which has been denounced through most of the Arab world as a separate peace neglecting Palestinian, Syrian and Jordanian demands.

Saudi Arabia and Jordan, both considered moderate U.S. friends, are a key to the treaty's success because of vital Saudi aid to Egypt and Jordan's assigned role in the Camp David framework for negotiations over the Israeli-occupied West Bank.

Brzezinski's team -- which includes President Carter's son Chip, Deputy Secretary of State Warren Christopher and Gen. David Jones, chairman of the Joint Chiefs of Staff -- could, however, point to the fact that neither Hussein nor the Saudis announced any concrete moves to punish Egypt for agreeing to the treaty or the United States for sponsoring it.

In fact, a high Jordanian official said that Saudi Arabia appears "very reluctant" to cut off funding for Egypt, which is estimated to run about $2 billion a year. The Saudi first deputy prime minister, Crown Prince Fahd, indicated strongly in an interview in this week's Newsweek magazine that the Egyptian aid will continue, at least partially.

Brzezinski, after flying from Am-man to Cairo, met with President An-war Sadat and emphasized the U.S. contention that the Egyptian-Israeli pact is "the beginning and the corner-stone of a comprehensive peace treaty in the region." Asked if he had obtained a pledge of continued Saudi backing for Egypt, he declined to respond.

[Observers in Cairo noted that Brzezinski seemed an odd choice for the mission to Saudi Arabia and Jordan since his recent statement, "Bye-bye PLO," seemed to write off Arab demands that the Palestine Liberation Organization be considered the representative of the Palestinian people.]

Before flying to Cairo, Brzezinski told reporters at Amman airport that his "useful and constructive" talks in Saudi Arabia and Jordan had "focused on movement toward a comprehensive peace settlement, common long-term regional interests and more immediate security threats."

But in both Amman and Riyadh, officials suggested that Brzezinski's langauge may have been overoptimistic.

Prince Saud, the Saudi foreign minister, said in a statement that his talks with the American mission were "frank and clear."

"the area's peace and stability can come only through a comprehensive, just settlement, which the Arab and Islamic nations and the Palestinian people desire," he added in the statement broadcast by the offcialSaudi radio.

"Frank" in diplomatic parlance indicates disagreement. Brzezinski, in a statement on leaving Saudi arabia after about 24 hours, said the talks there "widened understanding of complex and difficult issues," without claiming any agreement was reached.

Speaking after the Brzezinski mission's 2 1/2-hour talk here with Hussein and his top advisers, Sharif Abdul Hamid Sharaf, chief of the royal court, described them as "characterized by frankness."

He added that the talks were " constructive" and said he hoped they would "help in the ongoing dialogue between Jordan and the United States."

But top Jordanian officials reiterated the king's consistent refusal to get involved in the Camp David formula for West Bank autonomy, about which he was not consulted although he is expected to assume major responsibilities.

They also made it clear that Jordan does not agree with the recent U.S. thesis that the Middle East is threatened by Soviet or radical Arab threats.

"We think the main threat is lsraeli occupation and expansion," one official occupation and expansion," one official said. This in turn causes "a sense of alienation and disagreement and creates a climate conducive to outside exploitation," he added.

Jordanians and Saudis both want a comprehensive settlement. As Brzezinski's statements in Amman and Cairo indicated, the United States characterizes the Egyptian-Israeli treaty as the first step toward such an overall goal rather than as a separate peace.

Jordanian officials said that despite Gen. Jones' presence in the American delegation, specific military hardware procurement for Jordan did not come up at the talks with Hussein.

"No inducements had been offered." an official said, "and I don't see what inducements could make us -- or other Arabs -- change our positions."

Behind these words lay the growing Arab share in bankrolling Jordan -- 50 percent of whose budget is foreign-do-nated -- and the United States relatively declining stake, which still amounts to $250 million annually.

Summing up the reaction here to Brzezinski's trip, a Jordanian official, asked if he thought it was necessary, paused, then replied: "It was useful."