A senior aide of Palestine Liberation Organization leader Yasser Arafat praised President Reagan's Middle East peace plan here today, but he said that the PLO would strongly resist U.S pressure to recognize Israel as a condition for participation in the proposed talks.

Nabil Shaath, a member of the Palestine National Council, the parliament-in-exile of the umbrella guerrilla grouping and a close aide to the PLO chairman, said in an interview here:

"If the United States is really interested in forging ahead with peace talks, it can do so without any further commitment on the PLO's part.

"They can," he added, "interpret the Fez declaration as in effect satisfying the condition the United States has made for starting a dialogue with the PLO." The statement, which was issued at the conclusion of the recent Arab summit in Fez, Morocco, called for recognition of the right of all states in the region to live in peace.

He warned, however, that U.S. insistence on the PLO's recognition of Israel as a condition for starting a dialogue would be "too high" a price for the guerrilla organization to pay in return.

"We are willing to consider all these concessions as part of the negotiation process, and as an end result of it," he said. "But we will very strongly resist being pushed to leave our clothes at the door before sitting at the negotiating table."

The repeated U.S. insistence on its condition amounts to "pushing for the humiliation of the PLO," he said, "and the PLO will not accept that."

His argument was based on the premise that the war in Lebanon and Reagan's peace proposals as well as the Fez summit plan for settling the Palestinian problem provided an opportunity that should not be wasted by setting preconditons for starting talks.

Shaath, who recently returned from a visit to the United States, said that "there is a Palestinian desire for a dialogue, in fact partnership" with the United States in seeking a negotiated settlement of the Palestinian problem. He indicated that he was "most satisfied" with the outcome of his visit during which he met with senators and congressmen, but not with officials of the executive branch.

Under an agreement entered into with Israel by former secretary of state of Henry Kissinger, the United States is committed not to recognize the PLO until it publicly recognizes the Jewish state.

The Fez summit statement "contains the Reagan plan plus what is missing in it, namely, a clear commitment to a Palestinian state," Shaath said. He added the PLO was disappointed with the vagueness of the Reagan plan on the question of Palestinian representation, which the statement of the Fez plan assigned exclusively to the PLO.

Shaath revealed that a proposal had been presented and later rejected at Fez to grant Jordan a mandate to represent the Palestinians, though he did not rule out the possibility of a joint PLO-Jordanian delegation for future peace talks such as King Hussein has been suggesting.

Shaath described Egyptian-PLO relations as being in a transitional stage following the PLO's disappointment with Egypt's refusal to honor a request by Arafat to host about 6,000 fighters who were evacuated from Lebanon last August. Lately their ties have been strengthened, especially since Egypt agrees with the PLO that a linkage of an autonomous Palestinian entity with Jordan should not be imposed at the outset of any talks.

There remains, however, a basic disagreement between Egypt and the PLO, along with nearly all the other Arab nations, that results from the peace treaty the late president Anwar Sadat signed in 1979 with Israel. Sadat agreed to negotiate about the future of the occupied territories, in effect defying the Arab League's mandate to the PLO making it the sole representative of the Palestinians. In retaliation, most Arab countries broke diplomatic relations with Egypt and have not restored them.

President Hosni Mubarak, Sadat's successor, has been attempting to return to the Arab fold, but the treaty remains the major stumbling block.

Shaath said he was preparing for a visit to Cairo by Arafat late this month or early next month.

He said that Arafat would consider changing his present base in Tunisia to Egypt if details could be worked out with the Egyptian president.

"I think this is a place he would like to be in," he added. "I would not rule it out at all."