In this study, the effect of chitosan on cracking, corrosion behavior and deposition mechanism of cerium oxide conversion coating was investigated. The result showed that by adding chitosan to the solution the cracking was reduced noticeably and extremely high corrosion resistance coating was obtained when the value of chitosan was 0.01 wt%. In contrast, when the chitosan value was greater than 0.01 wt%, it was found that the mechanism of deposition changed and high porosity and powder coating of cerium oxide species were obtained.