Diagnosis method of earth screen corrosion and breakpoint of electric substation and its measurement and diagnosis system

The present invention belongs to the field of precision measurement and analysis of electricity. Said invention adopts D. C. power supply and makes it externally connected between two ground lead wires of ground screen to measure the voltage between ground lead wires and loop current to obtain input resistance between two ground lead wires, then the measured result and topological structure of the ground screen can be imputted into the diagnosis software to obtain the resistance value of every part of conductor, then said resistance value can be compared with the resistance value when said conductor is in good condition. Said invention has no need of excavating ground screen or cutting power, and can know that every conductor of ground screen is corroded to what extent and is broken or not so that of can ensure safe and reliable operation of power system.