The invention relates to a dual-purpose device for sand blasting and dust collecting, which comprises a dolly and a main pipe. A sand storage bucket and a dust collector are arranged on the dolly; thefront end of the main pipe is connected with a high pressure air supply device; a conical hole with a large front part and a small rear part is formed in the main pipe; a spray pipe with an inner diameter being isodiametric to an outlet of the conical hole is inserted to the rear part in the main pipe; a dust absorbing pipe connected with the sand storage bucket is arranged on a side wall of thebottom part of the main pipe; a dust collecting pipe communicating with the dust collector is arranged on a side wall of the top part of the main pipe; the sand absorbing pipe and the dust collectingpipe are located on the rear part of the outlet of the conical hole; a notch in butt joint with inlets of the sand absorbing pipe and the dust collecting pipe is formed in the front end of a side wallof the spray pipe; and a dustproof cover sleeves on the rear part, located outside the main pipe, of the spray pipe. The device is simple in structure and convenient to use. The movement distance ofsand in the pipeline is reduced, and the pipeline wear is reduced.