A clip structure for a USB wireless transmission device includes a housing, a flexible clip, a guide ramp, and a positioning wall. The flexible clip is pivotally disposed on the housing and is provided, on a surface thereof, with the guide ramp and the positioning wall. When the flexible clip is pivoted to a clipping position, the positioning protrusion of the housing happens to fall between the guide ramp and the positioning wall, and that the positioning wall restrains the positioning protrusion therein and prevents the flexible clip from pivoting and escaping from the clipping position. Therefore, a flexible object, to be clipped, is clipped in several folds so as to obtain a desirable clipping and securing effect.