UV visible spectrum of several camphor type β-diketone ring platinum complexes and their third order nonlinear optical properties at B3LYP / 6-31++G(d, p) level (Pt atom basis set with LANL2DZ nucleus potential) was theoretically investigated. The results show that the electronic transitions of molecules are mixed with metal-to-ligand charge transfer (MLCT), ligand transition (LC) and ligand to ligand transition (LLCT). Given the introduction of －OC2 H5 molecule in benzene ring, both the strongest absorption peak and the lowest energy absorption peak occurr blue shift. The introduction of phenyl group to β-diketone ring and fluorinated alkyl group on the another ligand phenyl ring can increase nonlinear optical properties. The introduction of electrondrawing group －CF3 in β-diketone made the lowest energy absorption peak red shifts occured, and at the same time, the introduction of alkoxy on the phenyl ring in another ligand benzene ring can also increase the nonlinear optical properties.