NEW YORK (AP) _ Mayor Edward I. Koch's name was resubmitted Wednesday for membership in the American branch of PEN, and this time he was voted in, the international organization of writers said.

Koch, the author of two books including one best-seller, was denied membership in the organization last month, less than a week before he threw a party at Gracie Mansion for foreign delegates to the 48th International PEN Congress in New York.

Authors Gay Talese and Kurt Vonnegut had proposed Koch for membership, but he was rejected when only eight of the 15 members of the membership committee voted last month.

On Wednesday, Koch's name was resubmitted by the authors at the committee's membership meeting, said Betty Fussell, the committee chairwoman. This time 11 of the 15 members voted for Koch's admittance into the organization, she said.

''I'm very, very grateful. From now on I will ask that whenever I'm introduced they drop all other salutations and simply say, 'Mayor Koch, author of two books and a member of PEN,'' Koch said on learning of the vote.

Koch's controversial 1984 memoir ''Mayor'' was on the New York Times best- seller list for 21 weeks. His second book, ''Politics'' was published last year, but did not make the list.

Talese said ''Mayor'' ''was offensive to many people described in the book, and I'm sure there are some PEN members who share some of the rancor toward the mayor that other politicians expressed. But he is an author and he was a genial host to PEN.''

But Mrs. Fussell said the initial rejection ''had nothing to do with whether he is a good politician or not, or because some people may like him or some may not.

''The membership committee is charged with deciding the literary merit of people applying,'' she said. ''And we did not feel that Mayor Koch came under the category of a man devoted to letters.''

The bylaws of American PEN, the largest of the 80 PEN centers worldwide, offer membership to writers and translators ''who have two or more published books of literary merit or one book of exceptional distinction.''