Abstract: Based on the analysis of the observation records from the three devices used by the Jiangxi Earthquake Early Warning Network (seismometer, strong seismometer, and intensity meter), the RMS value and power spectrum of the station site background noise indicate that the seismometer can effectively record the background noise in a wide frequency domain, while the strong seismometer can only effectively record natural noise above 0.1 Hz. In contrast, the intensity meter only records the noise of the device itself, and cannot effectively record microtremor. However, all three kinds of instruments can effectively record seismic events, and can be used for seismic location through the identification of initial movement of P wave. However, when determining the magnitude, the results of strong seismometer and intensity meter will be significantly larger than those of seismometer, so they are only used for reference in practical application.