Polythiophenes were prepared by chemical oxidative polymerization under the conditions of different reaction time t (1～12 h),temperature θ (-32～0 ℃),molar ratio of oxidant to thiophene n(FeCl3)/n(Th) =2～5,thiophene concentration c (Th) =0.05～0.20 mol/L.The structure and conductivity of the polythiophenes were characterized using Fourier transform infrared spectroscopy,ultraviolet and visible diffuse reflectance spectroscopy and megohmmeter.The results indicate that these preparation conditions could greatly affect the structure and conductivity of polythiophenes.The conductivity of polythiophene increase from 10-13 to 10-8 S/m with the increase of thiophene concentration from 0.05 to 0.20 mol/L.The highest conductivity of polythiophene at different reaction time is 10-10 S/m when the reaction time is 3 h.The conductivity of the polythiophenes prepared at different temperatures is all at 10-13 S/m level.When the n (FeCl3)/n(Th)increases from 2 to 5,the conductivity of samples increases from 10-13 to 10-10 S/m.The conductivity of the sample prepared by the treatment of direct filtration and washing increases 5 orders of magnitude over that prepared by the treatment of solvent volatilization at room temperature followed by filtration and washing.From the aspect of the balance of conductivity and cost,the optimized reaction conditions are:c(Th)=0.1 mol/L,t=3 h,θ =0 ℃,n(FeCl3)/n(Th) =2,and using direct filtration treatment on the products.Moreover,the optimized conductivity of the polythiophene is 2.49 × 10-8 S/m.