Abstract: This paper mainly investigates the influences of epoxy resins oligomer molecular weight on the electrical,mechanical,and thermal properties of the cured compound of bisphenol-A type epoxy resins system catalysed by tertiary amine (BDMA) accelerator and cured by anhydride (MeTHPA) curing agent.The results indicated that the strong effect of epoxy resins oligomer molecular weight on the cured compound properties,and the clear regularity of this effect.