Two U.S. senators, after meeting with Egypt's President Anwar Sadat today and Israeli Prime Minister Menachem Begin yesterday, said that both sides are determined to reach an agreement but that two difficult issues have yet to be negotiated.

Sen. Henry Jackson (D-Wash.) said the remaining issues are "not going to be resolved before December 10," the date on which Sadat and Begin are to receive the Nobel Peace Prize. He said it might be two months before an accord is ready for signing.

But Jackson, one of a group of senators who met with Sadat here today after talks yesterday with Israeli leaders, said that "the mood is still favorable. I see an agreement . . . the differences will be reconciled."

Sen. Jacob Javits (R-N.Y.) declined to say how long he thought it would take to wrap up the treaty.

"If given an opportunity," he said, the Egyptians and the Israelis would work out their differences "within a proximate time." But he said that "some forum would have to be found" for the talks to resume.

That was a reference to the fact that no formal negotiations are either in progress or scheduled. The senators agreed that more talks would be necessary on the issue of Palestinian autonomy and the relation of the treaty with respect to Egypt's commitments to Arab states.

Informal contacts are continuing - as Jackson put it, "the channels of communication are wide open" - and there has been speculation here that the United States would offer new formulas aimed at bridging the remaining gaps.

Sadat, smiling and relaxed as he received the senators and their party at his rest house on the Nile north of Cairo declined to discuss the status of the negotiations with the press. This is a time, he said, for "the Carter way of discretion," a reference to President Carter's appeal to both sides not to do their negotiating through the media.

That was in keeping with the posture Sadat has assumed since the Israeli Cabinet vote earlier this week to accept the draft treaty worked out at the Washington talks. He has refrained from critizing or attacking the Israelis and has let it be known through the Egyptian press and through Prime Minister Mustapha Khalil that Egypt is prepared for further negotiations.

According to Javits and Jackson, and to a variety of Egyptian officials, the two points on which Israel and Egypt still differ are:

Israel's demand that the Egypt-Israel treaty override or supersede Egypt's defense commitments to other Arab states.

Egypt's insistence that implementation of the treaty be linked to a timetable for the establishment of Palestinian autonomy in the Arab territories occupied by Israel, especially in the Gaza Strip.

This "linkage" issue was raised by the Egyptians before the start of the Blair House talks in October and has proved intractable.

However, it appears that the Egyptians have given some ground from the position that they were taking 10 days ago, when Sadat was insisting that the Israelis commit themselves to specific dates for the establishment of the home rule authority in the Palestinian territories. Then Sadat suggested that if Israel would not agree to this, Egypt would accept a formulation that dealt with the Gaza Strip first, restoring Egyptian administration there until the territory was joined to whatever developed eventually on the West Bank.

Jackson said of the linkage issue that "right now it's down to just plain Gaza." The problem, he said, is that the Israelis fear that if they accept a timetable or an interim Egyptian administration in Gaza, "that becomes a precedent for the West Bank."

According to accounts in today's Cairo press, Egypt would accept a compromise formulation offered on the linkage issue by the United States which reportedly calls for the establishment of Palestinian autonomy by the end of 1979, as a "basis for negotiations."

The other major outstanding issue, Egypt's mutual defense pacts with other Arab states, has attracted little attention during tedious weeks of haggling over linkage, but according to Javits is of crucial importance to Israel.

Israel, he said, fears that if another of the Arab countries on its frontiers became involved in hostilities with the Jewish state, it would invoke Egypt's treaty commitments to bring the Egyptians into the conflict.

Israel wants language in the treaty that would commit Egypt and Israel to carry out the provisions of the treaty between them "without regard to action or inaction of any other party and independently of any instrument external to this treaty," and that in the event of a conflict between their obligations under the Egypt-Israel treaty" and any of their other obligations, the obligations under this treaty will be binding and implemented."

Israel has accepted the draft treaty, because the proposed linkage to the evolution of Palestinian autonomy is not included in the text but contained in an annex or separate letter. The Egyptians have not specified which points of the treaty text they want amended, but the article on its other treaty obligations is clearly among them.

The acting foreign minister, Boutros Ghali, told the newspaper Al Ahram that "the existing Arab collective security charter signed in 1951 shall always prevail over all treaties and agreements concluded by Egypt in the future, including the Egypt-Israel draft peace treaty."

Officially, Sadat will not decide on his next move until after he receives a report from a high-level committee that is studying the status of the negotiations.

Sadat was expected to communicate his decision to Sen. Robert Byrd (D-W.Va.), the Senate majority leader, who is scheduled to come here Wednesday as a special emissary from Carter.