A system module of customizing a screen image based on a non-invasive data-extraction system, and a method thereof are disclosed. The system module is applicable to a machine controller controlling a machine, and sensors are disposed around the machine. In the system module, an image capture device receives an image of an original screen from the machine controller, and transmits the image to the non-invasive data-extraction system for extracting information, and a software control system integrates data measured by the sensors with the information, and combined the integration result with a customized screen image, and an extra control component is embedded in an original operation screen of the machine controller. The customized screen image is shown on the machine controller to display information by more visual manner. Furthermore, the signal receiving device and an HID simulation device can be used to provide a basic function of a KVM switch.