Abstract: In order to accurately predict the height of water flowing fractured zone under subcritical mining, mining thickness M, mining depth H, inclined length of working face L, dip angle of coal seam α, overburden mechanical properties R, overburden structure characteristics S were selected as the main influencing factors on the height of water flowing fractured zone under subcritical mining. Dimensionless relations between the height of water flowing fractured zone and M, H, L, α, S were established by dimensional analysis. Based on 30 sets of measured data, the optimal function relation of dimensionless relation was obtained by multiple regression. The prediction model is validated with field examples from two subcritical working faces, the prediction values are in good agreement with the measured values, and the relative errors are 3.64% and 2.93% respectively, the prediction accuracy of the prediction model can meet the field requirements of safe production in coal mine.