This machine is primarily for shot-blasting of steel structural parts, steel sheets and steel billets to remove the rusty spot, rusty layer and scale cinder on steel to obtain a uniform, smooth and glossy metal surface allowing improved coating quality and higher anti-corrosion performance. To ensure the high shot-blasting performance and extend the service of rollers, a high-chromium grinding-resistant sheath is installed on the room rollers to extend its service life by scores of times.