Amr Moussa also said the list of participating countries had to be coordinated before the organization backs the conference.
The Bush administration has proposed holding a conference in the U.S. to discuss the problems that are holding back peace talks between Israel and the Palestinians, and to pave the way for the creation of a unified Palestinian state.
"There are still many uncertainties surrounding the conference," Egyptian news agency MENA quoted Amr Moussa as saying.
"We do not know its agenda, its goals, and the participating parties, and I am sure that none of the Arab states will take part in this conference," he said.
At the same time, Moussa reaffirmed that the Arab countries welcomed the Bush initiative to revive the peace process in the Middle East "in all seriousness."
"The proposal by the U.S. president to hold an international conference has a number of positive aspects, although all participants must have a clear understanding of this forum's goals, otherwise it would be just another waste of time," he said.
The Arab League is a regional organization of Arab States in the Middle East and North Africa, formed in Cairo on March 22, 1945.