In order to accurately determine the "three zones" of overlying strata in 1202 working face of Pinggang coal mine, theoretical calculation, numerical simulation and experimental test in working environment have been applied to study the question of "three zones". And then the results of theoretical calculation and numerical simulation are that the range of caving zone and fracture zone are respectively 6.2-8.3m and 23.0-28.2m, which are consistent with the results of experimental test in working environment. With the aid of application of theoretical calculation and numerical simulation, it leaded to that the gas extraction flow rate is more than 1m³/min in the fracture zone. Thus, based on our method the precise heights of "three zones" are very helpful for improving the gas drainage quantity of high-level bore and high-level gas suction roadway in Pinggang coal mine. The methods and results of our research will be significant for guiding the practical production in the future.