Abstract: To more clearly reveal the reaction mechanism of Ptn+/-(n=1,2,3) and N2O,we used the density functional theoretical UB3LYP method to calculate the reaction mechanism of the reaction,and to learn the different between the platinum clusters and single platinum.At the same time,we compared the effect on the reaction, Ptn+/-(n=1,2,3)+N2O,by positive and negative charge.We have fully optimized all the geometry,and the intrinsic reaction coordinate (IRC) was then calculated to probe the reaction path and check if the correct transition state was located.The results showed that N2O activation mediated by Pt+ and Pt3+ were a typical spin-forbidden process,and the involving crossing between the ground state and the first excited state energy surfaces has been discussed.