The effects of propylene carbonate (PC，5％ by wt．)and γ-butylactone(γBL，10％ by wt．) upon the ionic conductivity of graft polyester network formed by PEO 800 macromer and unsaturated polyester containing LiClO4 were studied．The conductivity was found to be mainly determined by the concentration of LiClO4，with a maximum room temperature conductivity，σ298K=4.0—4.5×10-5Scm-1，at [Eo unit]／[Li+]=30．Little correlation was observed between glass transition temperature (Tg) and crossfinking degree for such polymer electrolytes，and the effect of LiClO4 concentration on Tg was also observed．The introduction of polar additives into the network increased the ionic conductivity greatly，while ex-erring little influence on Tg and degree of crosslinking．Thus，these may be con-tributed to the increase of ion mobility in the conducting pathway．The formation of graft IPN by using graft polyester and epoxy resin further improved the mechnical strength of the film sample，maintaining high conductivity at room temperature，σ298K=2.4×10-5Scm-1．