The utility model relates to a spiral sludge dewatering machine, belonging to a screw press dehydrator, which can reduce the sedimentation tank and the sludge concentration pool, and save the construction cost of the sewage station. Sludge dewatering machine using automatic update cake filtration technology replaces the traditional sieve filtration, self updating cake filtration technology to ensure the continuous stability of slurry dewatering separation effect, strong pressure generated by the screw diameter and pitch change, and small gap between swimming ring and the fixing ring, the sludge extrusion dehydration, solid-liquid separation equipment is a new type of.