This article reports the γ-ray induced copolymerization of chlorotrifluoropropene(CTFE), ethylene(E) and hexafluoropropene (HFP) in trifluorotrichloroethane (FC-113)served as solvent. It was mainly discussed how the reaction conditions affected the properties of terpolymer such as its composition, melting point, fused flowability, physicomechanical and hot-aging. The results are as follow:,1. The content of hexafluoropropene in the terpolymer increases with the mole ratios HFP/CTFE and HFP/E in the monomer feed.,2. When the value of mole ratio E/CTFE in the monomer feed is less than 0.65, and HFP/CTFE below 0.25, the melting point of the terpolymer will be≥235℃.,3. A quantity of -CF,3, pendant group connected with the backbone of the terpolymer would strengthen its fused flowability without decreasing its molecular weight. Therefore, the increase if M.I. has less influence upon its mechanical property. The relationship among the ,M.I., irradiation temperature(T), solvent feed froportion(ϕ)and hexafluoropropene content in the terpolymer(A) can be approximately shown by equation ,M.I,.=10,-3.8, • ,ϕ,2.8, • T,1.78,•(41.7A),1.4,.,4. Compared with the copolymer E-CTFE, the terpolymer possesses much better hotaging properties, but those of electricity remain unchanged.