Abstract: The monomer 4-trimethylsilylphenylacetylene (SPA) was synthesized and characterized by nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FT-IR). Poly(4-trimethylsilylphenyl-acetylene)(PSPA) were prepared by Pd(PPh3)2Cl2 and metal cocatalysts. PSPA is easy to be dissolved in chloroform, toluene and other organic solvents. It has good film-forming property, and high strength and thermal stability. TGA tests indicate that the 5% mass loss temperature is 300-310 ℃. Permeability coefficients (P) of PSPA membrane for CO2 gas reach 848 Barrer, and the membrane has higher permeation selectivity. Its separation factor reach 12.8, which has got rid of the limit of the Robeson’s upper bound actually.