In this paper，the copolymers of 1,4-diethynylbenzene and 1,4-butynediol with various kinds of ratio and their homopolymers are synthesized using (Ph₃P)₂ PdCl₂ as catalyst. The copolymers are of blackbrown color，insoluble in benzene， CHC1₃，THF and ethyl alcohol and infusible until 350℃. The higher the ratio of DEB in copolymerization，the larger the density (d₄²⁵) of copolymers，the higher the yield of copolymers and the less the swellability (θp) and average molecular weights between crosslinks (Mc ). When DEB/BD≥1/2 (mole ratio of monomers)，the best solvent of copolymers is benzene and the solubility parameter(δp) is 9.15 cal^0.5?cm^-1.5，when DEB/BD=1/5，the best solvent of copolymer is ethyl alcohol and δp is 12.7 cal^0.5? cm^-1.5.IR spectra of homopolymers and copolymers are drawn and studied and reaction mechanism of copolymerization is suggested.