Abstract: In recent years, BG2015R radon detector has been applied to radon observation in seismic industry as a new type of instruments. However, there are relatively few seismic stations using it for radon concentration observation as a formal instrument. The instrument was installed in Ningde seismic station in January 2019 and officially put into operation in January 2020 after trial operation. In the process of observation, certain understandings of the performance and operating characteristics of the instrument have been obtained. In this paper, two sets of radon measuring instrument systems, SD-3A and BG2015R, were carried out synchronous and comparative observation in series network in Ningde No.1 observation well, and the observation data and instrument operation were compared and analyzed, providing reference for other seismic stations in instrument selection, data analysis, system operation and maintenance.