Abstract: A kind of high-rigidity epoxy resin (5182 resin) was designed and its stiffness enhancement mechanisms in crosslinking network, the heat resistance properties and mechanical properties of epoxy resin were investigated. The results show that the stiffness of crosslinking network of 5182 resin is improved through stiff imide structure and more cross-linked points, the glass transition temperature is 228℃, and tensile modulus reaches 4 375 MPa. High-modulus carbon fiber (Domestic BHM3 and Toray M40J) reinforced high-rigidity 5182 resin composites were prepared, the interface properties, microstructure and the mechanical properties of high-modulus carbon fiber/high-rigidity epoxy resin composites were evaluated. Due to increasing modulus of resin and transferring of interface damage from carbon fiber surface to the resin area, high modulus carbon fiber/high-rigidity epoxy composites shows the highest interfacial shear strength (106.8 MPa) and excellent mechanical performance, especially flexible properties and interlaminar shear strength.