Passivation is an effective method to reduce the density of surface states. In this paper, the sulfur (S) passivation process on the 3C-SiC thin film surface was studied. The 3C-SiC thin films were passivated by three kinds of passivation solutions. The first passivation solution (passivation solution 1(#)) was the (NH4)(2)S and NH3 center dot H2O solution. The second passivation solution (passivation solution 2(#)) was prepared by adding S powder to the (NH4)(2)S and NH3 center dot H2O solution. The third passivation solution (passivation solution 3(#)) was prepared by adding HF to the (NH4)(2)S and NH3 center dot H2O solution until pH=7. The X-ray photoelectron spectroscopy (XPS) and Photoluminescence (PL) spectrometry were used to analyze the passivation effect. Both the XPS and PL results indicate that the SieS bonds and CeS bonds on the 3C-SiC thin films surface were the most abundant and the intensity of the PL peak was the highest after passivation by the passivation solutions 3(#). This shows that the passivation solutions 3(#) can reduce the density of surface states more effectively than other passivation solutions.