The present invention belongs to the long distance power supply system line connection state monitoring and fault positioning system technology field, in particular relates to a system of mobile power supply ground wire connection state real-time monitoring and fault positioning. The system of the present invention mainly solves the technical problems that a conventional method of using a resistance bridge to detect a ground wire connection fault is high in fault false alarm rate, and can not carry out the fault point positioning rapidly. The technical scheme adopted by the present invention is that the system of mobile power supply ground wire connection state real-time monitoring and fault positioning comprises a main monitoring device installed in a mobile transformer substation and a plurality of ground wire detection control devices installed in a mobile switch cabinet. The system of the present invention has the advantages of being able to alarm and position the faults accurately.