The invention relates to a preparation method and an application method of a photo catalyst for a high-efficiency photo-catalytic propylene epoxidation material. The preparation method comprises the following processes: preparing a titanium silicon molecular sieve TS-1 carrier by adopting a hydrothermal method and directly supporting Au and Ag bimetals on the carrier by utilizing an impregnation-reduction method to prepare a bimetallic-supported Au-Ag/TS-1 photocatalyst. The prepared photocatalyst is put in a fixed bed reactor; propylene, oxygen and diluent gas are introduced; photo-catalytic reaction is performed by taking a 100W ultraviolet mercury lamp as a light source to prepare propylene epoxide PO. The propylene can be efficiently and highly-selectively converted into the propylene epoxide, and the optimal generation rate and the selectivity of the propylene epoxide are 68.3 mu mol.g<-1>h<-1> and 52.3 percent respectively. The preparation method and the application method provided by the invention have the advantages of being simple in process condition, low in cost, good in repeatability and friendly in environment in the reaction process and can convert the propylene into an industrial product with higher value added.