In order to explore the mechanism of the outlet flow stability of one new type flow control valve for mine, the outlet discharge area was analyzed, and a new method with simple principle and high precision was proposed. Based on Fluent analysis software, the outlet pressure nephogram and the projection nephogram of outlet in the valve center plane under three kinds of displacement of valve core were obtained by simulation. Combined with the outlet structure characteristics, the calculation formula of outlet discharge area under different conditions was deduced; the variation curves of outlet discharge area with valve core displacement obtained by simulation analysis and theoretical derivation were drawn and compared by using MATLAB software to verify the accuracy of the theoretical calculation. The results show that the new mine flow control valve outlet discharge area characteristics can adapt to the change of inlet and outlet pressure, maintain the stability of the outlet flow, and has a certain reference value for the dynamic characteristics research in engineering.