Polyethylene glycol diacrylate (PEGDA), which contained acrylic end - groups, was prepared for solid polymer electrolytes(SPE) with a solid acid as catalyst. A novel type of SPE was obtained by mixing PEGDA with photoinitiator, LiClO,4, and plasticizer, and then being irradiated by UV light. The UV-curing, conducting and mechanical performances, depending on the type and the contend of plasticizer, were primarily discussed. The conclusion showed: plasticizing was an efficient method of improving the conductivity of UV-curable solid polymer electrolytes, and the conductivity of this kind of electrolytes was up to about 10,-4,S/cm when the mechanical performance of it was satisfying.