A series of vinylidene fluoride (VDF)／tetrafluoroethylene(TFE)／perfluoromethyl vinyl ether (PMVE) ternary copolymer with different composition were synthesized and characterized．The composition

crystallinity and gIass transition temperature of these eopolymers were examined with 19F-NMR

WAXD and DCS respectively．The experimental data showed that the composition of these ternary copolymers measured with 19F-NMR is consistent with those calculated from the apparent monomer reactivity ratios of the monomers．The fluorororubber was made from VDF／TFE/PMVE copolymer and its physical properties were measured．The results showed that the crystallinity of the copolymer decreased with the decrease of concentration of VDF and increase of PMVE in copolymer．The copolymers with low crystallinity have glass transition temperature between 245～251 K．The fluororubber can not be made from copolymers having high VDF composition because of the high crystallinity．The tensile strength of fluororubber decreased and its elongation at break increased with the decreasing of VDF concentration in the copolymer．