The passivation technology of silicon carbide was introduced from five aspects: post-oxidation annealing treatment, nitriding treatment, carbon cap, barium sandwich and post-deposition annealing of oxide. The density of interfacial states could be effectively reduced by improving the passivation process. The influence of these passivation processes on the interface state density of SiC/SiO2 was discussed, and the advantages and disadvantages of these passivation processes were analyzed. The passivation methods of annealing and nitriding after oxidation were mainly introduced. Finally, it was found that NO nitrogen technology could effectively reduce the interface density and improve the interface reliability, and it was suitable for manufacturing SiC MOS devices.