Abstract: This paper conducts a comparative study on the mechanical properties of GSM nylon （molybdenum disulfide filled nylon 6） and modified MC nylon （alkali-catalyzed polymerized nylon 6）, including tensile, compressive and shear properties. The experimental results reveal that both types of nylon exhibit a consistent layered mechanical characteristic: the surface layer has low strength and high elongation, while the core layer possesses high strength and low elongation, which is mainly attributed to moisture absorption. Modified MC nylon delivers superior toughness and compressive strength. Its core-layer elongation reaches 31.6%, compared with 22.2% of GSM nylon; its compressive strength ranges from 643 to 705 MPa, in contrast to 468 MPa of GSM nylon. Moisture absorption experiments verify that water absorption causes an obvious degradation in the strength of nylon. After boiling in water for 45 minutes, the tensile strength decreases by 13.7%, and drying treatment cannot fully restore its original mechanical performance. The shear strength of the two materials is approximately 0.6 times their tensile strength, with insignificant anisotropy. The research findings provide a reference for material selection in engineering applications. It is recommended that modified MC nylon be prioritized for high-load components, the adverse effect of ambient humidity on material performance should be fully taken into account during design.