The invention discloses a center of mass displacement monitoring device and method of a component in a temperature change condition, and belongs to the technical field of manufacturing quality prediction and control. The device comprises a base plate, a frame, a gasket, two displacement sensors and two pressure plates, a horizontal portion of the frame is arranged at the middle part of the base plate, two ends of a shaft component are respectively arranged in semicircular arc grooves of upper end surfaces of two vertical portions of the frame, semicircular arc grooves of the two pressure plates are respectively arranged at two ends of the shaft component, the gasket is arranged between a bottom surface of the end at which one vertical portion of the frame is located and the base plate, andthe two displacement sensors are respectively arranged at two ends of the base plate and located at two sides of the frame. According to the device and method, the displacement of the center of massof the shaft component, changing with the temperature, in the condition of loading a load can be monitored in real time.