The invention discloses a machine tool functional component reconfigurable monitoring system and a machine tool functional component reconfigurable monitoring method thereof. The system is based on a machine tool functional component reconfigurable monitoring hardware device with a hardware frame of an embedded monitoring unit and a sensor signal conditioning module and a reconfigurable monitoring software platform with a software frame of a system engine and functional components. According to monitoring requirements of different functional components of a machine tool, sensors are selected and a corresponding signal conditioning module reconfigurable monitoring hardware device is replaced; and the functional components are dynamically loaded on the reconfigurable monitoring software platform, and corresponding functional component monitoring subprograms are downloaded to a modularized embedded monitoring device on line, so that the different functional components of the machine toolare monitored. The system and the method contribute to quickly constructing a monitoring diagnostic system for the different functional components of the machine tool; the reliability, safety and efficiency of machining of the machine tool are improved; and the application and the development of the monitoring diagnostic technique in the domestic machine tool industry are also promoted.