Secretary of State George P. Shultz returned here today from Israel to begin an arduous, line-by-line discussion with Lebanese officials of draft ideas for an agreement on withdrawal of Israeli forces from Lebanon.

Shultz, who is shuttling between Jerusalem and Beirut in an attempt to break the four-month impasse in negotiations, came here with ideas stemming from his talks with Israeli Prime Minister Menachem Begin yesterday.

State Department spokesman John Hughes said the documents being worked on by Shultz and the Lebanese team headed by President Amin Gemayel were the most recent drafts of a possible agreement to emerge from the U.S.-sponsored talks.

These consist of a main document setting forth the terms for ending the state of war between Israel and Lebanon and an annex spelling out definitions of security arrangements to be established in southern Lebanon and the method of their implementation.

Shultz dropped his plan to return to Jerusalem tonight and decided to remain here until the talks with the Lebanese are completed. U.S. officials said it was likely that the negotiators would work through the night as they discussed the many disputed points in the approximately 24 pages of text.

Both U.S. and Lebanese officials cautioned that no one expected any major breakthroughs. Shultz, talking with reporters during the flight here, acknowledged that there has been no real change in the positions of either Israel or Lebanon. He left the impression that several more days of shuttling will be required before there is any real sign of whether an agreement is possible.

The main sticking points involve Israel's demand for security arrangements in southern Lebanon to protect itself against cross-border terrorist attacks. The United States is eager to obtain an agreement with Israel that will set the stage for withdrawal of Syrian and Palestine Liberation Organization forces as well as Israeli ones.

Since Shultz's arrival in Jerusalem Wednesday to begin his mission, Israeli officials have sought in a series of background meetings with reporters to give the impression that their demands are vital to Israel's security and do not infringe on Lebanon's sovereignty.

Specifically, Israel wants the principal responsibility for policing a security zone in southern Lebanon to be assigned to forces led by Saad Haddad, a cashiered Lebanese major and leader of a militia allied with Israel. The Beirut government has charged Haddad with treason for setting up an enclave under his rule in southern Lebanon near the Israeli border.

In addition, Israel seeks establishment of joint Israeli-Lebanese supervisory teams to roam the area, assignment of Israeli liaison officers to Lebanese Army units and the right for Israeli soliders to stay for varying periods at "logistical centers" in southern Lebanon.

A senior adviser to Gemayel, who talked with reporters here today on condition that he not be identified, charged that these proposals as currently defined by Israel are unacceptable because they represent an attempt to retain a disguised Israeli military presence with broad powers in southern Lebanon.

The official said Lebanese acceptance of these demands would make it very difficult for the Lebanese Army to gain the support and cooperation of the populace in southern Lebanon. In addition, he said, the impression that a residual Israeli military presence remained in Lebanon could cause Syria to refuse to pull out its troops.

On the flight here, Shultz acknowledged again that he hopes to go to Damascus for talks with Syrian President Hafez Assad but said he does not yet know when. Both the Israelis and the Lebanese are known to feel that Shultz should not visit Syria unless there is at least the broad outline of an agreement on Israeli withdrawal acceptable to Israel, Lebanon and the United States.