In order to make sure the safety of machining centers' working process, to avoid major accidents, to improve production rate and machine tool utilization rate, long-distance intelligent fault diagnosis system and reinforce operations management of machine tools were developed. Aimed at the physical truth of machining centers, by means of fetching alarm information of machining centers, Visual Basic (VB) was used to develop long-distance intelligent fault diagnosis system to monitor the operate states of the machining centers. Then the parameters were classified of computer numberial control (CNC) system and alarm information which have been extracted in order to look up and consult the information of CNC system immediately. Users can easily recognize the concerned states when the equipment is operating, so that, the purpose of fault diagnosing is achieved.