Physical cleaning refers to methods of cleaning membranes based on mechanical principles, mainly including hydraulic cleaning, ultrasonic cleaning, and gas pulse cleaning. Physical cleaning technology does not change the molecular structure of pollutants, does not cause environmental pollution, causes less harm to workers' health, does not significantly alter the interaction between pollutants and the membrane surface, and does not change the membrane structure or weaken its performance. Ultrasonic cleaning and gas pulse cleaning are still in the research stage for membrane fouling cleaning, while in practical engineering, the hydraulic cleaning method is often used for membrane cleaning.