A new earthquake detection demodulation system for monitoring several points and several parameters at the same time is proposed by using the linear sideband of super-fluorescent fiber source as an edge filter. The sensitivity of whole demodulation system is determined by the detecting sensitivity of source light. Through the optimization of light, the slope of light linear part is improved greatly. According to the rising and the falling of light, the system is divided into two parts each with four channels. Through the stimulation experiments of all the channels, the static wavelength sensitivities of the two parts are 887.5 mV/nm and -971.7 mV/nm, and their stain resolutions reseach 0.95με and 0.86με respectively. This demodulation system has high sensitivity, good stability, quick demodulation speed, etc. It is the most important is that it can realize real-time detection for several points and several parameters at the same time.