The preparation methods of nlyon thermoplastic composite mainly include hot-melt prepreg method and in-situ polymerization method.Compared to the in-situ polymerization method， the hot-melt prepreg method always has higher cost and lower efficiency in producing composites.In reponse to the urgent demand for efficient and low-cost manufacturing of nlyon thermoplastic composite，this article takes fiber reinforced nylon 6 composites as the research object，summarizes the research progress of in-situ polymerization methods for preparing nylon 6 thermoplastic composites，including casting，centrifugation and rotation，pultrusion，and liquid molding.It focuses on the liquid molding process of this thermoplastic composite and briefly describes its development direction.