Abstract: One new solvent free impregnating resin based on unsaturated polyester with modified diphenylene ether is prepared. It can be quicky cured and resisted high temperature for class H in a short curing time and low evaporation losses. Marganous ocaprylate and pentaacruthritol acrylate were prepared and used as an accelerator and volatimatter inhibiter respectively. It was concluded that those accelerator and volatimatter inhibitor were effective.