To obtain the optimal dust-exhausting airflow volume on the premise that the gas concentration in the fully mechanized caving face of high-gas coal mine can be fully diluted to the safe range, gas-respirable dust (RD) coupling dispersion under various inlet airflow volumes (Q) were simulated numerically. The results show that when Q2100 m(3)/min, the gas concentration in the mining face is fully diluted. RD is distributed in basically the same way under various airflow volumes. When Q is raised from 2100 m(3)/min to 2500 m(3)/min, the RD concentration falls continuously. However, Q continues to increase, RD concentrations no longer decrease significantly. when Q is promoted to 2700 m(3)/min, the phenomenon of dust reentrainment occurs. Therefore, 2500 m(3)/min can be regarded as the optimal dust-exhausting airflow volume. Field measurement and verification shows hat the average relative errors between the simulated results and measured results of airflow velocity, gas concentration and RD concentration are 5.8 %, 4.13 % and 5.18 % respectively, which means that the numerical simulation results boast high reliability. (C) 2020 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.