The invention discloses a micro-seismic monitoring system and method. The micro-seismic monitoring system comprises an optical fiber sensing device and a data acquisition device, wherein the optical fiber sensing device and the data acquisition device are connected with each other. The optical fiber sensing device can be laid on the ground and/or arranged underground, and is used for transmitting a laser signal emitted into an optical fiber and transmitting a reflection laser signal of each point of the inner wall of the optical fiber. The data acquisition device is used for emitting the laser signal into the optical fiber, receiving the reflection laser signal of each point of the inner wall of the optical fiber sensing device, converting the reflection laser signal into a second seismic signal, and processing the converted second seismic signal to determine the intensity and the spatial geometrical position of an underground source. According to the invention, the micro-seismic monitoring system is used to carry out micro-seismic monitoring, which can improve the reliability and the accuracy of a micro-seismic monitoring result.