Abstract: In this paper, an analytical verification method for valve discharge under saturated steam is studied by taking the pressurizing system stop valve as an example. Comparison of the values of valve discharge test under small opening and low pressure difference with the theoretical calculation value shows that the deviation is within the acceptable range. The value of valve discharge under full opening and full pressure difference is obtainedby putting the test values into the equation deduced. Comparingn it with the value of valve discharge by ANSYS analysis under full opening, we can found that the deviation between the actual derived discharge and the theoretical calculation discharge is 2.73%. The results show that under the condition of insufficient test capacity, the discharge rate of saturated steam by the valve can be analyzed by coupling thedischarge test in small opening and low pressure difference with the theoretical derivation.