The invention relates to a trolley-type chain mud scraper. A main structure of the chain mud scraper consists of a driving device, a guiding device, a guide rail component, a mud scraping trolley, a hoisting device and a safety protection device; the driving device consists of an electric motor with positive and negative rotation functions, a decelerator and a driving chain sprocket; the guiding device consists of a drag chain guiding device, a tension device and a drag rope guiding device; the guide rail component consists of a rail and an embedded plate; the mud scraping trolley consists of a frame, a running idler wheel, a lateral turning prevention idler wheel, a derailment prevention idler wheel, a link drive mechanism, a large mud scraping plate and a small mud scraping capable of turning, a mud scraping arm, a mud scraping arm bearing block and a trolley enclosure; and the hoisting device consists of a portal frame, an idler wheel and a hoisting mechanism. The trolley-type chain mud scraper can be widely used for removing mud out of a horizontal sedimentation (clarification) tank.