The invention discloses a spray device for a washing tower in the technical field of gas treatment. The spray device comprises a washing tower body and an exhaust pipe for discharging the gas washed by the washing tower body, one end of the exhaust pipe is installed on the top end of the washing tower body, a detergent tank, a filling layer member for mixing gas and detergent, and a defogging layer member for defogging exhaust gas are arranged in order from bottom to top inside the washing tower body, a detergent circulator is arranged on one side of the detergent tank, a wash nozzle is arranged on that detergent circulator, the washing nozzle is located above the filling layer member. According to the invention, by utilizing the design of the filling layer component, the gas can be conveniently stayed in the filling layer for a long time, so that the gas can be fully treated by using the detergent. Moreover, when the tail gas is discharged, the tail gas can be detected, and when the tail gas does not meet the standard, the recirculation treatment of the tail gas can be realized, thus improving the treatment quality of the gas.