The invention relates to an 
ion beam radiotherapy dosage 
verification method based on 
water equivalent coefficients. The 
ion beam radiotherapy dosage 
verification method based on the 
water equivalent coefficients includes the following steps that A, CT image data of a 
cancer patient are obtained, a treatment planning 
system (TPS) is utilized for plan design according to a CT-
water equivalent coefficient transformation curve, and 
ion beam 
radiation parameters are recorded after the plan is determined; B, a virtual three-dimensional water phantom CT image is generated based on the water equivalent coefficients, the 
ion beam radiation parameters are transplanted to the water phantom through the TPS, dosage optimal computation is carried out again, and three-dimensional rasterization 
dose distribution in the water phantom is obtained; C, an 
ionization chamber is placed at an interest point in the three-dimensional water phantom, interpolating calculation is carried out in the three-dimensional rasterization 
dose distribution according to the three-dimensional coordinates of the sensitive volume of the 
ionization chamber in the water phantom, and planned dosage of the interest point is obtained; D, the 
ion beam radiation parameters designed as planned control a medical heavy-ion accelerator to perform simulated 
irradiation on the water phantom, and the measured absolute dosage value of the interest point for the 
ionization chamber in the water phantom is compared with the planned dosage.