Homogeneous polymerization of p-diethynylbenzene initiated by nickel acetylide Ni(C ≡ C C_6H_4 C ≡ CH)_2(PPh_3)_2has been investigated in terms of different solvents, addition agents, atmosphere gases, catalyst concentrations, monomerconcentrations and polymerization temperatures. The yield and catalytic efficiency approach 88% and 11. 1 kg polymer/molNi, respectively, under the optimum conditions: [cat] = 0.01 mol/L, [M] = 1.0 mol/L, NEt_3/cat (mol ratio) = 3～5, 1,4-dioxane/toluene (volume ratio) = 1 and T = 25℃ for 5 h. The polymerization rate equation can be expressed as R_p =k_p[M][cat]~2, where k_p= 0.47 L~2. mol~(-2)·S~(-1) (25℃). The overall polymerization activation energy was found to be203 kJ·mol~(-1). Poly(p-diethynylbenzene) so obtained is soluble in THF, CHCl_3 and toluene with weight-average molecularweights as high as 27, 100 and a rich-trans extended π-conjugated polyene chain structure with pendent groups ofp-C_6H_4C≡CH. Homogeneous polymerization of p-diethynylbenzene initiated by nickel acetylide Ni (C≡C C_6H_4 C≡CH) _2 (PPh_3) _2has been investigated in terms of different solvents, addition agents, atmosphere gases, catalyst concentrations, monomer concentrations and polymerization temperatures. The yield and The catalytic efficiency approach is 88% and 11. 1 kg polymer / mol Ni, respectively, under the optimum conditions: [cat] = 0.01 mol / L, [M] = 1.0 mol / L, , 1,4-dioxane / toluene volume ratio = 1 and T = 25 ° C for 5 h. The polymerization rate equation can be expressed as R_p = k_p [M] [cat] ~ 2, where k_p = 0.47 L ~ 2 . The overall polymerization activation energy was found to be203 kJ · mol -1. Poly (p-diethynylbenzene) so obtained was soluble in THF, CHCl_3 and toluene with weight-average molecular weights as high as 27, 100 and a rich-trans extended π-conjugated polyene chain structure with pendent groups of p-C_6H_4C≡CH.