The chalcone derivatives (E)-3-(4-(allyloxy)phenyl)-1-phenylprop-2-en-1-one (Blank-Cha), (E)-3-(4-(allyloxy)phenyl)-1-(4-hydroxyphenyl)prop-2-en-1-one (Oxhydryl-Cha) and (E)-3-(4-(allyloxy)phenyl)-1-(4-methoxyphenyl)prop-2-en-1-one (Methoxy-Cha) were prepared. Further, polysiloxane UVA filter (WPUF) was prepared by grafting Methoxy-Cha onto polymethylhydrosiloxane chain via silica-hydrogen addition reaction. The chemical structures of the products were identified by NMR, LC-MS and FTIR, and proved that the chalcone derivatives and WPUF were successfully prepared. The effects of different substituents on the UV absorption properties and cytotoxicity of chalcone derivatives were investigated. The results showed that the chalcone derivatives had a molar absorbance coefficient ε > 10000, and Methoxy-Cha was the least cytotoxic. The chemical structure of WPUF did not change after protection from light for 6 months and heating at 90 ℃ for 12 h. The loss of UV absorption capacity was only 30.46% after simulated sunlight exposure for 4 h. Moreover, WPUF did not exhibit cytotoxicity at concentrations of 250 μg/mL and below. In vitro penetration test measured an average penetration depth of 11 μm in the stratum corneum of WPUF. The SPF value of WPUF was determined in vitro to be 36.21, which is comparable to commercial sunscreens.