Cyclone desanding technique is separating solid phase from drilling mud by centrifugal force, it can be used in geological prospecting, petroleum and gas industry and metallurgical industry. Automatic cyclone desander adopts cyclone-separating technique; retrieves the defects of traditional desander, such as unsatisfied solid phase separating effect and underflow channel blocking. So purifying quality of drilling mud and desanding efficiency are largely improved, the blocking area can be automatically broken with less working time and cost.