<p>A comprehensive investigation on the microstructure evolution, kinetic behavior, and catalytic activity of TiCl₄/MgCl₂-Al(i-Bu)₃ catalyzed styrene and isoprene copolymerization contributes to elucidating the active center characteristics, stereoselectivity, and copolymerization mechanism of supported Ziegler-Natta catalysts for the copolymerization. This study systematically observed the effects of three critical parameters, polymerization time, temperature, and Al/Ti molar ratio, on catalytic efficiency, copolymer composition, and sequence distribution. Advanced characterization techniques were employed to elucidate the active center dynamics. The acyl chloride quenching method quantified active center concentration, multiple Flory superposition analysis revealed active center distribution, and X-ray photoelectron spectroscopy (XPS) deciphered titanium valence state evolution during polymerization. It was demonstrated that increased copolymerization enhanced isoprene polymerization activity while suppressing styrene polymerization activity. The content of Ti⁴⁺ decreased gradually with the corresponding increase of Ti³⁺ and Ti²⁺, suggesting the existence of redox-mediated activation pathways. Two distinct active center configurations were resolved: low-steric-hindrance C*-2 centers preferentially initiated <i>cis</i>-1,4-polyisoprene sequences, while high-steric-hindrance C*-1 centers demonstrated enhanced <i>trans</i>-1,4-polyisoprene and isotactic polystyrene formation. Based on these mechanistic insights, we propose a novel copolymerization model providing new understanding of Ziegler-Natta copolymerization mechanisms for styrene-diene systems.</p>