Egyptian President Hosni Mubarak strongly urged Defense Secretary Caspar W. Weinberger today to visit Jordan, warning that the United States is damaging the chances for Middle East peace by leaving Jordan's King Hussein out in the cold.

Late today Weinberger had decided tentatively to pay a brief and unannounced visit to Amman, partly in response to Mubarak's urging and partly as a sign of U.S. support for the king, according to knowledgeable officials. U.S. officials said a trip to Jordan had been under consideration for at least two weeks.

Mubarak, speaking with Weinberger in a private session with only two or three other officials present, said the United States should reconsider its refusal to sell Jordan many of the weapons systems it is seeking, including fighter jets and antiaircraft missiles.

Egyptian leaders were not pleased with Weinberger's response that, while he understands the problem, the administration is constrained by Congress and other factors, the officials said. Mubarak recently returned from Amman, where he reportedly urged Hussein to overcome some of his bitterness at what the king perceives as repeated U.S rebuffs.

Mubarak's private session with Weinberger was the centerpiece of a day of meetings focusing on the Middle East peace process and U.S. military aid to Egypt.

Egypt urged the United States to "activate its role in the peace process," according to Osama Baz, director of the Foreign Ministry. U.S. officials had arrived here prepared to reassure Cairo that the administration will take a more active role after the Nov. 6 election if President Reagan wins.

Weinberger urged Mubarak to meet with Israeli Prime Minister Shimon Peres, officials said. Mubarak has let it be known that he does not favor such a meeting unless major concrete steps advancing the peace process were certain to emerge from it.

Baz said today that Egypt has "no objection whatsoever to thawing" relations with Israel and that when Tel Aviv decides to withdraw from Lebanon and improve its policies in the West Bank and Gaza Strip, Cairo will "reciprocate."

Perhaps reflecting Egyptian frustration with U.S. unwillingness to demand concessions of Israel or make concessions to Jordan, Baz said that he understands that any administration "is usually too busy this part of the year."

"They are too cautious," he said. "They don't want to take any chances, and they prefer to maintain a situation as it is and not be asked to take any positions that could generate any controversy."

Baz also said, however, that recent U.S. efforts may help lead to an Israeli troop withdrawal from Lebanon "in a short period of time." He said that Egypt is willing to help promote such a withdrawal -- in part, he suggested, by supporting a larger United Nations force for southern Lebanon.

"The talks that were held on this matter with the help of the U.S. have made significant progress in the last few days," Baz said. "The remaining points are, in my opinion, surmountable." That assessment was the most optimistic that any official involved in the process has voiced recently, although the Israeli government has indicated that it wants to withdraw its troops. U.S. officials here said that they do not know what talks Baz was referring to and that they do not believe an agreement is imminent.

Weinberger told Egyptian officials about Peres' recent visit to Washington. Peres is seeking sharply increased U.S. military and economic aid, and Baz said today that Cairo believes the United States has a "legally binding" commitment to maintain an equal level of support to Egypt.

Baz also said that Egypt wants to discuss the issue of rescheduling payments on its $3.7 billion military debt to the United States.

The question of U.S.-Jordanian relations has assumed more importance here since Hussein became the first major Arab leader to resume relations with Egypt since Cairo signed the Camp David peace accords with Israel in 1979.

Jordan has been rebuffed by Washington, often because of congressional pressure, in its efforts to buy F16 or F20 fighter jets, mobile Hawk antiaircraft missiles and shoulder-fired Stinger missiles.

An administration attempt to train and equip a Jordanian rapid deployment force also was rejected after the secret proposal contained in the classified budget request was revealed. The administration did not seek congressional approval for the program this year but may try again in fiscal 1986, officials said.

Weinberger's visit to Jordan would be intended to show U.S. support for Hussein's decision to recognize Egypt and to assure him that the Reagan administration, if it wins another term, will redouble its efforts to provide the king with suitable military equipment, U.S. officials indicated. The United States has been concerned by reports that the king is "feeling isolated" and that he is considering further arms deals with the Soviets, one official said.