Preparation of xanthate silane coupling agents ethyl xanthate propyl triethoxysilane (EXS) and octyl xanthate propyl triethoxysilane (OXS) with different alkyl chain lengths by phase transfer catalysis. Two xanthate-based silane coupling agents were used to modify silica and reinforce styrene-butadiene rubber to study the processing properties, vulcanization properties, mechanical properties, wear resistance, compression properties, dynamic mechanical properties of styrene-butadiene rubber/silica composites. At the same time, the composites modified by Bis-[γ-(triethoxysilyl)propyl]tetrasulfide (Si-69) and end-capped mercaptosilane coupling agent (NXT) were prepared as a comparison to explore the feasibility of the new coupling agent to replace NXT and Si-69 in the rubber industry. The results showed that the OXS-modified composites with long alkyl chains had the lowest Mooney viscosity, high processing safety but a slightly slower vulcanization speed, and the composites modified with EXS had low processing safety but The vulcanization speed is faster; the mechanical properties, hardness and wear resistance of the composite modified by the new coupling agent are higher than those of the NXT modified composite, and the rolling resistance is lower; the silica modified by EXS has better dispersion in the rubber matrix, and the interaction between filler and rubber.