The embodiment of the application discloses a microseismic data noise suppression method and system. The method comprises: microseismic data are obtained, wherein the microseismic data includes at least one piece of seismic trace data; seismic data at a first time window position in first seismic trace data in the microseismic data are obtained; according to the preset number of fitting orders and a preset universal model, fitting is carried out on seismic data at the first time window position and fitting models corresponding to the fitting orders at the first time window position are determined respectively; according to the multiple fitting models at the first time window position and the seismic data at the first time window position, a target fitting model is determined among the multiple fitting models; on the basis of the target fitting model, noise data of a target sample point at the first time window position are determined, wherein the target sample point is a time sample point at the middle position in the first time window; and with the noise data, noise suppression is carried out on the seismic data corresponding to the target sample point. Therefore, direct-current noise data in the microseismic data can be suppressed effectively.