A process for a monitor working in a DPMS mode applies when a monitor ends a working mode and enters the DPMS mode. In the DPMS mode, when the signal processor of the monitor detects there is no signal input to the connecting interface, the signal processor will be off and inform the micro-controller to open the signal detecting function to find whether there is a signal input to the connecting interface. When the micro-controller detects there is no signal input for a certain of time, the micro-controller will enter the sleep status. As a result, the purpose of saving the electricity can be achieved.