The utility model relates to the technical field of computer wire harness fixing, in particular to an anti-collision and anti-dropping structure of a computer host, which comprises a bottom frame, a holding fixing mechanism is arranged on the front side of the bottom frame and is used for fixing the bottom frame on a host case, and a plurality of groups of wire harness anti-dropping tightening mechanisms are arranged on the rear side of the bottom frame in parallel. The wire harness anti-falling tightening mechanism comprises a fixed cover, a cover body and a winding frame, the fixed cover is arranged on the bottom frame, the cover body is arranged on a port of the fixed cover in an opening and closing mode, meanwhile, a power shaft is rotationally arranged in the fixed cover in a penetrating mode, the winding frame is arranged at the inner end of the power shaft, and two sets of groove holes are formed in the side wall of the fixed cover in a right opposite mode; when the wire harness winding device is used, a wire harness is put in from the groove hole in the rear side, bypasses the winding frame and then is pulled out from the groove hole in the front side, the power shaft rotates to drive the winding frame to rotate to wind and tension the wire harness, the overall length is shortened, the situation that an overlong part is dragged on the ground is avoided, and the cover body is closed at the moment.