The electric sputum suction unit can be used for suctioning sputum and other secretions for children in hospitals, and may also be used in negative suctioning in surgical operations on children. The machine adopts oil-free lubricating pump, avoiding the pollution of oil mist. The pump requires no daily maintenance and servicing; and the overflow protection device in the machine prevents liquid from flowing into the pump. The machine is characterized with small volume, light weight and high mobility.