The analog water radon observation is an important measurement item of precursory observation in earthquake monitoring and prediction of China.During the process,a series of ma-nual observation methods,i.e.,regular sampling,bubbling,measured value calculation,and data warehousing are adopted.These observation methods,which are backward and have a large degree of human operation error,will affect the quality of observation data to a certain extent.As a key link in the process of analog water radon observation,the bubbling operation directly affects the accuracy of water radon measurement.In this paper,the traditional analog radon bubbling device was improved,and a set of automatic bubbling device suitable for all types of analog radon instruments was developed,which can solve the problem of large interference to the measured value of water radon caused by the non-standard operation during the process of artificial bubbling.The automatic bubbling device can reduce the difficulty of bubbling operation,reduce man-made ope-ration error,so as to improve the quality of water radon observation data.