Abstract: The outhors have made many field experiments and room analogy.The results show that,for spring water,the measured radon content and its dynamic state of water from tubes at different positions are different.For thermal water wells containing free gas, the amount of gas entering sampling tube is related to the ratio of sub-tube flow cap-acity to principal tube flow capacity, tube position and tube diameter.A detailed co-mparision is made for the characteristics of dissolved radon, gas radon and mixed radon.It provides a base for water-well remake and anomaly confirmation, A discus-sion is made, based on experiment and theory,for the constraint action of flow capacity on response capacity of water point.Finally, we suggert such a technical idea that we can use different sampling devices and observe multicomponent to get more inform-ation.