Taking glass fiber warp-knitted biaxial composite materials as the research object， this study investigates the influence of warp-knitted binding yarns on their mechanical properties. Since binding yarns serve as the key unit connecting warp and weft reinforcement yarns， it significantly influences composite material performance. Therefore， we prepare warp-knitted biaxial composite materials containing low-elasticity polyester binding yarns and similar biaxial composite materials without binding yarns. Samples are fabricated using a vacuum infusion molding process， the tensile， compressive， three-point bending， and low-speed impact properties are tested， and the mechanisms are analyzed through microscopic morphology analysis. The results show that the tensile strength of the composite materials with binding yarns increases by 21.67%， the compressive strength increases by 17.50%， the bending strength and modulus increase by 10.01% and 6.54%， respectively， and the low-speed impact energy absorption rate increases by 9.92%. The binding yarns enhance interlaminar bonding， coordinates yarn stress distribution， and suppresses fiber buckling and delamination propagation， thereby optimizing the composite materials’ load distribution and energy dissipation capabilities， significantly improving its overall mechanical properties.