A series fan structure with multistage frame body includes a first main body, a second main body, a first frame and a second frame. The first main body has a first fan frame having a first opening and a second opening. The second main body is correspondingly serially connected to the first main body. The second main body has a second fan frame having a third opening and a fourth opening. The third opening corresponds to the second opening. The first frame is correspondingly serially connected to one side of the first fan frame with the first opening. The first frame and the first fan frame together define a first flow passage. The second frame is correspondingly serially connected to one side of the second fan frame with the fourth opening. The second frame and the second fan frame together define a second flow passage.