Based on the three⁃step production process of anion polymerization between styrene and butadiene, a three⁃step model of SBS polymerization process was established using Polymer Plus, to analyze the sensitivity of the raw materials including styrene and butadiene, the catalyst (butyl lithium) and chain transfer agent (tetrahydrofuran,THF) , as well as the impact of the input amount on the molecular weight, polydispersity index (PDI), and yield of the SBS product, guiding further actual production process. The results indicated that purifying the monomers and increasing the input amount for styrene and butadiene can improve the polymerization degree and molecular weight of the product. Besides of that, increasing of the input amount of styrene could decrease the the PDI value. The catalyst had a significant effect on the properties of the product. Thus, the input amount of butyl lithium must be strictly controlled in actual production process. Different from catalyst, chain transfer agent (THF) had a slight influence on the properties of the product and could be used to adjust the molecular weight and degree of polymerization of the product on a small scale without affecting the production yield.