BONN, West Germany (AP) _ U.S. Attorney General Edwin Meese told Bonn officials today that Washington would accept a decision to try a suspected TWA hijacker in West Germany instead of extraditing him to the United States, government sources said.

Meese said the United States wants assurances the Lebanese Shiite Moslem, Mohammed Ali Hamadi, would be tried on murder and air piracy charges, the West German sources said. Those are the charges for which Hamadi was indicted in the Unites States.

The sources, who spoke on condition of anonymity, said Meese was concerned West Germany might try Hamadi only for possession of dangerous explosives, the charges for which he was arrested at Frankfurt airport Jan. 13.

Concern for the lives of two West Germans kidnapped in Lebanon after Hamadi's arrest prompted Bonn officials to decide against extraditing Hamadi to the United States, security sources said earlier. The kidnappers have demanded the 22-year-old Hamadi's release.

Interior Minister Friedrich Zimmermann assured Meese the more serious charges would be filed against Hamadi, the Bonn government sources said.

Meese also told the West Germans the United States would supply them with further evidence against Hamadi, the sources said.

Hamadi is under indictment in the United States on air piracy and murder charges in the June 1985 hijacking of a TWA jet to Beirut. A U.S. Navy diver was killed and other Americans were held hostage during the 17-days ordeal.

''Meese said the Americans were worried that we would just charge Hamadi with explosives charges,'' one West German source told The Associated Press. ''We told him that would not happen, that he would also be charged with air piracy and murder.''

''Zimmermann also made it clear that releasing Hamadi was never seriously considered,'' the source added.

''Meese said the Americans would fully support the trial here,'' the source said in a telephone interview.

President Reagan said Monday he would be satisfied if Hamadi were tried in West Germany.

Meese met separately with Zimmermann and Justice Minister Hans Engelhard today in what U.S. spokesmen said earlier would be an attempt to convince them to honor the U.S. request for Hamadi's extradition.

Meese, speaking to reporters outside the Justice Ministry, refused to give any details of his nearly two hours of talks with Engelhard or the meeting with Zimmermann.

Meese said the Bonn government has not made a final decision on what would be done with Hamadi. He said the Cabinet was scheduled to make the decision Wednesday.

''We had a very frank and complete discussion. It would be inappropriate to comment now on a decision that has not yet been made,'' the attorney general said. ''The decision will be made tomorrow. I will not comment further.''

Engelhard told reporters he and Meese discussed the Hamadi case ''in full detail from our various points of view.''

Asked whether Meese had repeated the U.S. demand for Hamadi's extradition, Engelhard said ''It is known that the Americans want extradition. The decision will be made tomorrow, and I don't want to comment now.''

Security sources, speaking on condition of anonymity, told the AP that Chancellor Helmut Kohl and other ranking officials had already decided to reject the U.S. extradition request.