Abstract: With Na-montmorillonite (Na-M) as the research object, cetyl trimethyl ammonium bromide-silane coupling agent KH550 (CTAB-SCA) modified Na-M was prepared by using CTAB and SCA as the modifier and deionized water and absolute ethyl alcohol as the solvent. The influences of the mass ratio of CTAB and deionized water, the mass ratio of SCA to absolute ethyl alcohol and the mass ratio of carbon black to CTAB-SCA modified Na-M on the mechanical performance and flame retardant performance of CTAB-SCA modified Na-M/rubber composites were explored. The microscopic morphology, mineral composition and composition structure were characterized by SEM, XRD and FTIR, respectively. The results show that the prepared CTAB-SCA modified Na-M/rubber composite has good mechanical performance and the flame retardant performance (tensile strength is 18.9 MPa, tear strength is 42.9 kNm^-1 and limit oxygen index is 31.51%) when the mass ratio of carbon black to CTAB-SCA modified Na-M is 20:30, the mass ratio of CTAB to deionized water is 13.5:1050 and the mass ratio of SCA to absolute ethyl alcohol is 0.30:15. The mixture of CTAB-deionized water can reduce the polarity between slice layers of CTAB-SCA modified Na-M to improve lipophilicity. The mixture of SCA-absolute ethyl alcohol with surface hydroxyl of CTAB-SCA modified Na-M in chemistry improves dispersion. The carbon black is the main reinforcing material, CTAB-SCA modified Na-M is main flame retardant and auxiliary reinforcing composites in CTAB-SCA modified Na-M/rubber composites.