Propylene epoxidation catalyst in-situ modification method

The invention discloses a propylene epoxidation catalyst in-situ modification method. The propylene epoxidation catalyst in-situ modification method achieves in-situ modification of propylene epoxidation catalysts filled inside a reactor and comprises purging a propylene epoxidation catalyst bed inside the reaction through air or nitrogen, then sequentially, inletting peroxide-containing aqueous solution for modification, then switching to a mixed solution composed of organic solvent, water and additives for modification, and lastly switching to an organic solvent-containing and hydrogen peroxide-mixed aqueous solution for modification, thereby achieving the aims of eliminating impurities and side reaction activity centers on the surface of the catalysts, dredging pores and improving the dispersing performance of reaction materials. The propylene epoxidation catalyst in-situ modification method can shorten reaction activating time and improve catalyst activity as well as product selectivity and stability and meanwhile is simple, wide in application range, capable of effectively shortening the starting time and applicable to epoxypropane industrialized production with direct propylene epoxidation.