A dynamic simulation model of a hollow fiber membrane module has been developed by deriving new transient mole fraction balances, energy balances, and gas velocity equations based on mole balances. The adopted flow type of the membrane module is a counter-current flow for the recovery of methane from coalbed methane (CBM), which is a form of natural gas extracted from coalbeds and is composed of mainly methane (up to 80-99 vol%) and minor impurities (CO2, N-2, etc.). This study assumes that the CBM feed gas for the dynamic simulation consists of 90% methane and 10% carbon dioxide. In the simulation model, CBM feed gas is supplied into the bore side feed, and purified methane rich gas, the retentate gas, is produced from the product side of the bores. Carbon dioxide rich gas, the permeate gas, is discharged from the outlet end of the shell side. The simulation results are very similar to the experimental data of Airrane Co., Ltd. in Korea. This paper presents the effects of design and operating conditions on the performance, and investigates the transient behaviors of membrane modules using the validated simulation model.