Corn stalk cellulose (CS)/used rubber powder (RP) composites were prepared by mixing, the silane coupling agent 3-Mercaptopropyl trimethoxysilane (KH590), r-Aminopropyltrieth oxysilane (KH550), isopropyl dioleic (dioctylphosphate) titanate (HY101) and bis-(gamma-triethoxysilylpropyl)- tetrasulfide (Si69) were used to modify the interface of composites. The effects of the CS and coupling agents on the mechanical properties, thermal properties, interfacial morphology and structure of the composites were investigated, respectively. The results showed that the addition of CS could effectively improve the mechanical properties of the composites. Compared with the untreated composites, the interfacial bonding between CS and RP was significantly improved by the coupling modification treatment, and the tensile strength and elongation at break of composites with Si69 increased by 3.13 MPa and 10%, respectively, the Si69 showed the best coupling modification effect, followed by KH590, then KH550 and HY101 when the CS content was 25 pph (part per hundred) and coupling agent 1.5 pph, and the thermal decomposition temperature increased by 30 degrees C.