To enhance the thermal property of diglycidyl ether of bisphenyl A (DGEBA),(polyhydroxyl) POSS (SP2-POSS) modifier was prepared using a reaction of (γ-aminopropyl)POSS (A-POSS) and phenyl glycidyl ether (PGE).Different fractions of SP2-POSS (8% ,15% ,30% ,45% ,60% and 75% ) were added into diglycidyl ether of bisphenyl A (DGEBA) to modify the network and enhance the thermal property.The results show that the crosslinking-network density,curing heats and glass transition temperature are enhanced due to the existance of the polyhydroxyls.The network containing 75% SP2-POSS possesses the best thermal properties.