Abstract: According to the characteristics of gas emission in coal particles and Darcy’s law,authors proposed a gas e- mission differential equation of cylindrical coal particles,which was solved with finite volume method. Dimensionless numbers were imported to carry out the dimensionless criterion of the differential equation and the discretized equation obtained with finite volume method. A computer program was coded in Visual Basic to solve the equations. According to results,the gas pressure variation curves of different times and space nodes within the coal particles,the gas curves of desorption speed variation,gas accumulative desorption amount variation curves and gas content variation curves were obtained. The dimensionless curves was analysed,an application example was given,then the laws of gas desorp- tion and emission within coal particles were obtained.