Influence of geometric and cutting parameters of cemented carbide cutting tool on reliability of cutting tool has become more and more mature,yet influence of its physical and material parameters on reliability is still blank.In view of this,cutting test and fatigue crack growth test of YT05 cemented carbide cutting tool are conducted to measure such data as the original crack size,growth size,times of impact loading,number and time of cutting tool in failure,and stress distribution of cutting tool is also obtained by simulating cutting process of tools.Mathematical models on dynamic reliability and dynamic reliability sensitivity of cutting tool are derived respectively by taking machining time and times of impact loading into account,thus change rules of dynamic reliability sensitivity to physical and material parameters can be obtained.Theoretical and experimental results show that sensitive degree on each parameter of tools increases gradually with the increase of machining time and times of impact loading,especially for parameters such as fracture toughness,shape parameter,and cutting stress.This proposed model solves such problems as how to determine the most sensitive parameter and influence degree of physical parameters and material parameters to reliability,which is sensitivity,and can provide theoretical foundation for improving reliability of cutting tool system. Influence of geometric and cutting parameters of cemented carbide cutting tool on reliability of cutting tool has become more and more mature, yet influence of its physical and material parameters on reliability is still blank. In view of this, cutting test and fatigue crack growth test of YT05 cemented carbide cutting tool are conducted to measure such data as the original crack size, growth size, times of impact loading, number and time of cutting tool in failure, and stress distribution of cutting tool is also obtained by simulating cutting process of tools. Mathematical models on dynamic reliability and dynamic reliability sensitivity of cutting tool are derived respectively by taking machining time and times of impact loading into account, thus change rules of dynamic reliability sensitivity to physical and material parameters can be. Theories and experimental results show that sensitive degree on each parameter of tools increases gradually with the increase of machining time an d times of impact loading, especially for parameters such as fracture toughness, shape parameter, and cutting stress. This proposed model solves such problems as how to determine the most sensitive parameter and influence degree of physical parameters and material parameters to reliability, which is sensitivity , and can provide theoretical foundation for improving reliability of cutting tool system.