This study aimed to develop an accurate correction method of errors in the water radon value caused by a change in the emanometer K value.First,we investigated current methods used to correct radon values and found obvious differences among them.This is because none of these methods capture the real change in the K value.Therefore,in this study,we adopted the curve fitting method to investigate changes in the K value.Fitting models examined in this study include linear,quadratic,logarithmic,cubic,and exponential models.We performed curve fitting for 12 K-value groups and obtained their curve fitting equations.Results revealed that the fitting degree of the quadratic curve was the best.Therefore, we adopted the quadratic curve method for correcting the radon values of No.22 well,which is located in Wushan county,Gansu province.To test the accuracy of the corrected radon value results after curve fitting,we determined the correspondence among changes in the radon value from all types of correction methods and earthquakes.Results revealed that the shape of the corrected radon value curve using the curve fitting method not only has good reproducibility prior to strong earthquakes but also well synchronizes with the curve shapes of water radon values obtained from other stations around the epicenter before a strong earthquake.Furthermore,these results show that it is necessary to correct the water radon error using the K-value change mechanism.The use of the curve fitting method to correct the radon value error caused by a change in the K value is an innovative technique and a significant contribution to the field.