The current study focuses on the cavitation jet characteristics of the jet nozzle for ship cleaning under different water depths. The nozzle of a dual-chamber self-excited oscillation pulsed jet nozzle is numerically studied under four depths of 10m, 25m, 50m and 100m by using the Rayleigh-Plesset cavitation model. The cavitation degree, fluid velocity distribution and turbulent kinetic energy distribution of the nozzle under different water depths are studied and analyzed. The results indicate that the cavitation in the internal flow field of the dual-chamber self-excited oscillation pulsed jet nozzle is greatest with relatively high fluid velocity and the turbulent kinetic energy is highest in the rear chamber and rear channel. However, the cavitation, fluid velocity and turbulent kinetic energy in the external flow field are significantly reduced. With the increase of the water depth, the internal flow field of the nozzle is almost unaffected, while the external flow field is greatly affected with increased cavitation number and gradually reduced cavitation degree, fluid velocity and turbulent kinetic energy, and thus weakened cavitating cleaning effect. The numerical research method can provide references for the underwater ship cavitation cleaning.