Iran came into the tie looking to build on its emphatic win over Chinese Taipei, with the Central Asian side taking the lead in the 14th minute after Jafar Asadi broke into the box after surging down the left to drill a low shot into the bottom left corner.
Lebanon fought back in the second half and Eyad Eid equalized the match in the 65th minute.
Iran will play Palestine on Friday, while Lebanon face India.