King Hussein of Jordan today called upon the Palestine Liberation Organization to join him in drawing up a plan for a Jordanian-Palestinian federation roughly along the lines proposed by President Reagan.

Speaking to members of his Consultative Council and other leading Jordanian political figures about the future of the territories occupied since 1967 by Israel, the king said the time was "ripe" to open a dialogue with the PLO "to formulate the relationship which will exist between Palestinian and Jordanian entities in the form of a federation."

"We have to prepare this federation formula and present it on the basis of our commitment to the right of self-determination of both the Palestinian and Jordanian people," he said.

The king's remarks, coming only three days after the massacre of Palestinian civilians in West Beirut, were interpreted here as meaning he is still ready to become involved in new peace talks despite the general Arab revulsion at the killings.

The monarch had first publicly indicated his interest in President Reagan's peace intitiative last week when he called for new negotiations on the establishment of a Palestinian self-governing entity "in association with Jordan." This was before the latest events in West Beirut, however, and it was feared in Western diplomatic circles here that the massacre might have caused him to change his mind.

Hussein in his speech accused Israel of being responsible for the killings, charging that they were an attempt by Prime Minister Menachem Begin to deal a direct blow to U.S. prestige and policy in the region and show that Washington could not keep its commitments to the Arabs.

He compared the killings in the two Palestinian camps in Beirut last week to the massacre of Palestinians at Deir Yassin in 1948, carried out by the Israeli terrorist organizations led by Begin and current Foreign Minister Yitzhak Shamir. Some 240 men, women and children were killed.

The Jordanian monarch went out of his way to urge a positive Arab response to Reagan's Middle East initiative, arguing that it constituted a significant shift in U.S. policy toward the region and was not in contradiction with the eight-point peace plan adopted by Arab leaders at their summit in Morocco two weeks ago.

"We shouldn't consider the Arab peace plan as an answer to the American move," he said. "The Arab plan is a stand we are committed to and will defend. But this does not mean we should take a negative stand toward the American initiative, which we think has some positive elements."

The king's appeal to the PLO to engage in talks with him on the American-proposed idea of a Jordanian-Palestinian federation came only days before a scheduled visit here by PLO leader Yasser Arafat.