The present invention relates to a switch monitoring method and a switch monitoring system, a railway line management method and a railway line management system. Electric signal of a switch motor during pulling of the switch can effectively reflect status of the switch, when the switch is in a stable state, electric signal of its motor is very steady during pulling of the switch; however, when the switch is in an unstable state, there will be different degrees of fluctuation in electric signal of its motor during pulling of the switch. Thus, the invention may be used to identify state of a switch by monitoring electric signal of a switch motor, and further take different measures based on different states of the switch. With these measures, accidents due to switch failure may be effectively reduced, and train delay time may also be reduced through proper line management.