Deformed coal is a kind of coal that the primary structure has been damaged; even the internal chemistry constituents and structure have been changed. The deformed coal has close relationship with gas outburst. The objective of this work is to explore microscopic reasons to gas outburst by comparing the differences of adsorption and diffusion for methane in deformed coal and corresponding undeformed coal using molecular simulation of grand canonical Monte Carlo (GCMC) and molecular dynamic (MD) simu...