Abstract：The hydrothermal reaction method is used to react the melamine suspensionat 200 ℃ to produce an intermediate product.The intermediate product is then calcined to directly produce a two-dimensional Graphite phase carbon nitride g-C3N4 nanosheet (WCN), which is stripped from the bulk g-C3N4 (CN) and the g-C3N4 nanosheets (OCN) obtained by the traditional thermal oxygen method were compared.The catalysts were characterized by SEM, XRD, FTIR,Raman,AFM and PL instruments, and the photoelectrochemical and photocatalytic properties of the catalysts were discussed.The results show that both methods achieve CN peeling.The two-dimensional nanosheets of WCN and OCN have the same crystal structure and composition as CN. The specific surface areas of WCN and OCN are 4 and 3 times that of CN, respectively.Photoelectrochemical analysis shows that WCN has better carrier migration and separation efficiency, and has better photocatalytic activity.Under visible light, the photocatalytic degradation rate of methylene blue (MB) by WCN reached 82 %, which was 2.4 and 6.7 times that of OCN and CN, respectively. The photocatalytic degradation process conforms to the first-order kinetic equation.WCN has excellent stability and reusability.