Abstract: In order to evaluate the site-selecting quality of each seismic station, the background noise of each station is calculated and analyzed by using the digital record of the background noise of the 62 stations in Xilinguole area. According to the calculating results of root- mean-square (RMS) and power spectrum density of these seismic stations, and combining with the international specification for digital seismic observation techniques, it is concluded that the background noise level of each station is relatively well, they are all within the standard range and are divided into four levels. The analysis of the background noise of the site selection of the scientific seismic array is not only conducive to the study of the site response and magnitude correction of these stations after the construction of the scientific seismic array, but also to the evaluation of the seismic monitoring capability of the scientific seismic array in Inner Mongolia.