W/Si emulsifier (EMCD) with UV absorption was prepared by grafting Chalcone derivative (E)-3-(4-allyloxygen)phenyl-1-(4-methoxy-phenyl)propyl-2-alkene-1-ketone (Methoxy-Cha) and allyl polyether APEG-400 onto hydrogen-containing silicone oil chains. The chemical structure of the product was determined by NMR. EMCD can stabilize the emulsion with the best stability when the ratio of silicon to water ranges from 25:75 to 17.5:82.5, and the mass fraction of EMCD is about 2%. The maximum total efficiency was 5.237% when EMCD was combined with MBBT. Compared with KF-6017, EMCD can increase the SPF value of sunscreen lotion from 21.76 to 33.29, and the average UVA/UVB ratio from 0.433 to 0.587, enhancing the broad spectrum protection capability of sunscreen lotion.