Hydraulic-drill-rig drill rod synchronizing device

The utility model discloses a hydraulic-drill-rig drill rod synchronizing device. A bit shank spline matched with a tail-end spline of a synchronizing body is installed at a bit shank of a hydraulic rock drill, and a synchronizing body sliding disc is installed at the top of the synchronizing body. An air cylinder is installed on the hydraulic rock drill and connected with an air pipe, and the synchronizing body sliding disc is located below the air cylinder. A spring is connected to the tail end of the synchronizing body, two drill rod stop blocks are installed on a drill rod, two synchronizing body stop blocks meshed with the drill rod stop blocks are installed on the synchronizing body, and meshed working threads are arranged at the tail of the bit shank and the interior of the drill rod. The hydraulic-drill-rig drill rod synchronizing device has the advantages that it can be guaranteed that the threads of the bit shank and the threads of the drill rod still can synchronously rotate under the looseness condition through meshing of the stop blocks and the splines, so that rod changing can be normally carried out.