easier for our examiner to understand the present invention the following detailed description with reference to the accompanying drawings of embodiments are given for example but such preferred embodiments are not intended to limit the scope of the present invention for simplicity like numerals are used for like elements for the description of the specification of the present invention referring to fig2 3 3 a 4 4 a for a sectional fan frame structure of a first preferred embodiment of the present invention the structure comprises a fan frame 10 and the fan frame 10 is composed of two units 11 a and a circular plate frame 12 and the units 11 a are rectangular frame bases but ordinary persons skilled in the art can substitute it with a frame base of another shape and each unit 11 a has a circular opening 111 and a fastener 20 disposed on a specific position of the unit 11 a and the fastener 20 can be a hook or an embedding groove and an axle seat 113 is connected to the middle of the opening 111 of one of the units 11 a through a rib 114 and the axle seat 113 has a circuit not shown in the figure for turning on the fan the circular plate frame 12 is formed by enclosing a rectangular plate and a fastener 20 is disposed separately on both sides of the circular plate frame 12 and the fasteners 20 are latched to the corresponding positions of the fasteners 20 of the units 11 a further the circular plate frame 12 has a plurality of protrusions 121 integrally formed with the circular plate frame 12 by a punching method and at.