Radon is sensitive to the change of strata stress before and after the earthquake. It is an effective element for tracing the structure and seismic activity, and accounts for a large proportion in China’s earthquake precursor observation network. In recent years, due to the aging and updating of instruments, the calibration of radon meters at many stations has been restricted, which further affects the accuracy and reliability of radon observation data. In this paper, the high-precision AlphaGUARD radon meter is used to calibrate the BG2015R radon meter in Ningde No.1 well by using fresh well water and fixed sources with a certain concentration. The relative errors between the new K
value and the old K
value are 2.83% and 1.1% respectively, and the calibration results meet the observation requirements of China Earthquake Networks Center; At the same time, the average and consistency of the measured values of AlphaGUARD radon meter and BG2015R radon meter in the calibration experiment are calculated and analyzed, and the value suggestions for the calibration of the two sets of instruments are given. The flow and method of the calibration experiment described in this paper can provide a certain technical reference for the calibration of the radon meter operating in the network.