The influences of technological condition on thickness and refractive index of the SiON films preprared by plasma enhanced chemical vapor deposition and the influence of SiON/SiNx stacked film on passivation performance on P-type silicon wafer are investigatied. The results show that the refractive index of SiON film varies from 1.48 to 2.1 and thickness varies from 30-60 nm by changing the gas flow of NH3 and the gas flow ratio of N2O/SiH4. The pressure and RF power mainly affect the thickness of the film. The greater the pressure, the higher the RF power, the faster the deposition rate is and the thicker the film is. The influences of temperature on the film thickness and refractive index can be ignored. The passivation shows that the passivation performance of P-type silicon film after annealing SiON/SiNx stacked films with a gas flow ratio of N2O/SiH4 20 and 30 in the absence and the presence of NH3, is best, which the implied voltages and the lifetimes of minority carriers are 652 mV, 56.7 μs and 649 mV, 50.8 μs, respectively. The passivation effect of SiON/SiNx stacked film is superior to that of the reference SiNx film.