1,3-Pentadiene can undergo anionic copolymerization with styrene derivatives to give special alternating sequence-controlled copolymers, which have significantly applications in the area of impact resistance of resins and toughening agents. In this article, a series of copolymers were obtained via anionic copolymerization using styrene (ST), 1,3-pentadiene (PD) and p-methyl-Styrene (MST) as monomers and n-BuLi as initiator. The copolymerization kinetics analysis as well as the microstructure of copolymers was investigated in detail and some results show that :(1) the hopolymerization activities order is ST>MST>>PD and all polymerization kinetics analysis all show the evolution of -ln(1-x) versus t is strictly linear, and the copolymer yield easily reaches up to 100%; (2) the real-time NMR analysis show the composition of PD in poly(PD-alt-ST) or poly(PD-alt-MST) is constant (FPD=50%), and the NMR spectra results together with the reactivity ratio data all prove the alternating sequence microstructure. Moreover, the PD monomer has priority to undergo 1,4-addition reaction to give the predominant 1,4-units; (3) the alternating copolymerization and terpolymerization proceed in a living and controlled manner, and the molecular weight is well agreement with the theoretical value, also the molecular weight distribution is lower than 1.10; (4) in the case of n(MST)/n(ST)/n(PD)=1/1/2 system, the composition of PD in terpolymer is constant (FPD = 0.5) and the evolution of styrene composition (FST or FMST) versus x is strictly linear; (5) based on the dual-alternating copolymerization strategy of PD, the possible alternating polymerization mechanism was proposed.