外部环境压力变化是影响煤样瓦斯解吸规律的主要因素之一。为研究煤体在常压与多级降压环境下瓦斯解吸规律的差异，以型煤为研究对象，通过自主研发的含瓦斯煤体带压解吸系统，对不同吸附平衡压力下的型煤试样分别进行常压解吸和多级降压解吸实验，对比分析其解吸特性，并总结不同经验公式对解吸数据的适用性。结果表明：2种解吸环境下的瓦斯解吸量随时间的变化均呈现“快速上升-逐渐变缓-趋于稳定”；在多级降压解吸过程中，相同解吸时间内的瓦斯解吸量随解吸压力的降低而增大，解吸达到平衡状态所需时间变长，不同吸附平衡压力下的累计瓦斯解吸量与解吸压力呈负相关；乌斯基诺夫式和文特式对常压及各解吸压力下的多级降压过程都具有较高的拟合度，而巴雷尔式只能描述降为常压后的瓦斯解吸过程。

The change of external environmental pressure is one of the main factors affecting the gas desorption pattern of coal samples. In order to study the difference of gas desorption under atmospheric pressure and step-down pressure, we conducted the experiments of atmospheric pressure desorption and step-down pressure desorption on coal samples under different adsorption equilibrium pressures by using the self-developed gas-bearing coal desorption system, to compare and analyze their desorption characteristics and summarize the applicability of different empirical formulas to the desorption data. The results show that: the gas desorption volume in both desorption environments shows a “rapid rise - slowing down - stabilizing” with time; in the process of step-down desorption, the gas desorption volume in the same desorption time increases as the desorption pressure decreases, and the desorption takes longer time to reach the equilibrium state. In the process of stepwise desorption, the amount of gas desorbed in the same desorption time increases with the decrease of desorption pressure, and the time required for desorption to reach the equilibrium state becomes longer, and the accumulated gas desorption volume at different adsorption equilibrium pressures is negatively correlated with the desorption pressure.