The invention provides a method for monitoring and positioning railway rockfall. According to the method, a local server is arranged at a side slope along a railway, multiple microseismic positioning subsystems are arranged along the railway, each of the microseismic positioning subsystems comprises multi-channel data collection modules connected to a local server through a synchronous triggering line and a data transmission line and four microseismic sensors connected to input ends of the multi-channel data collection modules. The local server sends a synchronization signal to each microseismic positioning subsystem through the synchronous triggering line, receives microseismic information collected by each microseismic positioning subsystem through the data transmission line, then calculating seismic source parameters according to the microseismic information, and uploading the seismic source parameters to a monitoring center through the Ethernet. According to the method, according to vibration waves generated by rockfall impact on a ground collected by the multiple microseismic sensors, the coordinates of a seismic source point are calculated, the method has the advantages of a simple structure of a monitoring device, low cost, convenient installation and maintenance, and high anti-interference ability, and relevant personnel can be helped to timely discover and eliminate security risks.