Display omitted •Aminopropyl triethoxysilane is introduced to tailor the organic/inorganic interfaces in the CSSE based on the –NH2 effect.•The hydrogen bond interaction between –NH2 and PEO can enhance the interface interaction.•Lone pair electrons on N can react with electron-deficient -CN in solvent ACN and promote the uniform dispersion of LLZAO.•Lone pair electrons on N can complex with Li+ and promote the dissociation of Li salts and uniform Li+ diffusion. Composite solid-state electrolyte (CSSE) with integrated strengths avoids the weaknesses of organic and inorganic electrolytes, and thus become a better choice for all-solid-state lithium battery (ASSLB). However, the poor dispersion of inorganic fillers and the organic/inorganic nature difference leads to their interface incompatibility, which greatly destroys the performance of CSSE and ASSLB. Herein, silane coupling agent (SCA) aminopropyl triethoxysilane (ATS) is introduced to tailor the organic/inorganic interfaces in CSSE by the common chemical bridging effect of SCA and the special amino effect (hydrogen bond and lone pair electron effects). It is found that the hydrogen bond interaction between –NH2 and polyethylene oxide (PEO) enhances their interface interaction. And the lone pair electrons on nitrogen atom allow it to react with solvent acetonitrile and promote the uniform dispersion of ceramic fillers. Moreover, the lone pair electrons can complex with Li+, which promotes the dissociation of Li salts, uniforms Li+ diffusion and inhibits the Li dendrite. Thanks to the above merits, the interface compatibility and stability of organic/inorganic CSSE are much enhanced by innovatively introducing ATS, showing high ionic conductivity and superior mechanical/thermal stability. The ASSLB with this modified CSSE exhibits excellent electrochemical performance with a reversible capacity of 140.9 mAh g−1 and a capacity retention of 94.4% after 280 cycles. These achievements offer a new insight into improving the stability of organic/inorganic CSSE interface and promoting their applicability into ASSLB.