Traditional meeting, telephone or paper document cannot meet requirements of coal mine informatization. The paper introduced a mobile office system of coal mine from views of development scheme, function modules and key technologies. Coal mine personnels can do usual office work through the system such as data inquiry about six systems of coal mine safety production, daily communication, information diffusion and obtainment and so on. The application shows construction of the system makes coal mine personnels know situation of safety production at the first time and improves timeliness and correctness of information management.