Abstract: In order to solve the problems of low yields and serious pollution to environment in synthesis of megastigmadiendiones,the experiments on catalytic synthesis of megastigmadiendiones from ionones with metal salt catalyst(such as CuCl,PbCl₂,CeCl₂,AlCl₃,NiCl₂,etc.) and tert-butyl hydroperoxide as an oxidant in imidazolium hexafluorophosphate(PF₆) ionic liquid were conducted.The results showed that using CuCl as a catalyst,4,7E-megastigmadien-3,9-dione and 5,7 E-megastigmadien-4,9-dione were efficiently synthesized from α-ionone and β-ionone,and their yields were up to 68% and 55%,respectively.The catalytic system of CuCl/PF₆ could be reclaimed and used repeatedly for 6 times.In that system,CuCl in its nanoparticle form catalyzes the reaction.