Abstract: This paper describes the results of studies on the anionic copolymeri-zation of butadiene and styrene initiated by n-BuLi-THFin cyclohexane. From the experimental data obtained, integral and differential composition distribution curves of incoporated styrene in copolymer at various B/Sratio have been ploted. By adjusting conc.of THEand n-BuLi, B/S, ratio and temperature, the molecular design of butadiene-styrene copolymer with different molecular weight, T_g, styrene content and microstructure of polybutadienc chain segment could be realized.