A computer system, remote control monitoring system, and remote control monitoring method are provided to instantly provide the local display screen of the local computer to the remote computer for remote real-time display. The remote control monitoring system is arranged in the local computer and has a signal receiver and a remote controller. The signal receiver receives the video signal from the processor, executes the signal transforming process to generate the video signal in different standards. The remote controller executes a network compressing process on the transformed video signal to generate the network transportable video data, and transmits the data to the remote computer for displaying the corresponding remote display screen on the remote computer. The present disclosure enables the implementing of the out-of-band remote displaying.