The invention belongs to the technical field of cleaning equipment, and especially relates to an automatic sewage suction device for a pool. The automatic sewage suction device comprises a motor, themotor drives a hollow rotating base to rotate, a sewage suction pipe for cleaning the bottom of the pool is arranged on the rotating base, a sewage discharge shell is arranged on an outer shell of themotor, the sewage suction pipe, the rotating base and an inner cavity of the sewage discharge shell are sequentially connected in a communicating way to form a sewage discharge channel, and a liquidsuction device is further arranged on the sewage discharge channel. The sewage suction pipe comprises a plurality of telescopic rods which are movably arranged together, an elastic piece is arranged between every two adjacent telescopic rods, and the elastic pieces provide pushing force for a telescopic rod at the outer end to extend outwards. When the liquid suction device sucks liquid, impurities can be sucked into a sewage suction nozzle and discharged along with the sewage discharge channel, meanwhile, the motor drives the sewage suction pipe to rotate at a low speed for one circle throughthe rotating base, and the purpose of cleaning the pool by 360 degrees is achieved. In addition, the telescopic rod abuts against the side wall of the pool all the time under the action of the elastic pieces, the length of the sewage suction pipe can be automatically adjusted according to the shape of the pool, and cleaning of different pool shapes is achieved.