Epoxy-siloxane prepolymer was synthesized through hydrosilylation between 1,2-epoxy-9-decene and hydrogen-terminated polydimethylsiloxane in the presence of a catalytic amount of Karstedt's catalyst [platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane], then cured with cationic light initiator under ultraviolet light to obtain UV-curable epoxy-polysiloxane resin. The reaction conditions for the synthesis of the prepolymer were optimized. The structure of the synthesized prepolymer was characterized by FTIR and 1HNMR. The properties and morphology of the cured film were tested by thermogravimetic analysis (TGA), differential scanning calorimetry (DSC), contact angle, alkali resistance and alcohol resistance, gel rate, Shore A hardness, and fracture surface morphology. The results showed that under the conditions of reaction temperature 75 ℃, reaction time 8 h, dosage of catalyst's active ingredient 0.009‰ (based on the total mass of hydrogen-terminated polydimethylsiloxane and 1,2-epoxy-9-decene, the same below), the reaction degree was 93.95%. When the dosage of photoinitiator BL9380 was 3% (based on the mass of the epoxy-siloxane prepolymer, the same below), and the curing time was 20 s, the cured resin had the best comprehensive performance. The surface activity energy was 18.4~18.8 mN/m, the gel rate was 93.9%, and exhibited dood alkali resistance and alcohol resistance with Shore A hardness of 37. The cured resins exhibited good thermal stability with corresponding temperatures of maximum decomposition rate of 437.6 and 511.3 ℃ in air, and 13.9% of residual weight ratio at 780 ℃.