Abstract: In order to study the influence of hole angles on hydraulic flushing effect, hydraulic flushing tests have been carried out with the method of experimental research in 27001 floor return air roadway. By using the means of the statistics of coal flushing quantity, gas drainage quantity detection, data analysis and so on, we studied the coal flushing quantity and gas drainage effect under different conditions. The results show that coal flushing quantity of hydraulic flushing and gas extraction effect increase along with the decrease of the hole angle; the best unit coal flushing quantity of the large angle hole（50 ° and above 50 °） of Zhongmacun Coal Mine is 1 t/m to 1.5 t/m, and the unit coal flushing quantity of small angle hole （below 50 °） is 1.5 t/m to 2 t/m.