The invention discloses a magnetic flux detection-based earth screen state comprehensive evaluation system, comprising two parts of hardware and program software; the hardware comprises a magnetic flux detector and a computer, which are communicated with each other; the magnetic flux detector is used for collecting an earth screen corrosion degree signal; the computer is used for reading the data fed back by the magnetic flux detector for comparing with preset corrosion data and analyzing, thus generating a comprehensive evaluation report. The comprehensive evaluation report is fast conveniently generated by comparing and analyzing the detection data and the data in a database, so power transformation maintaining personnel can very conveniently, comprehensively and accurately master the earth screen state, effects of rapidness, accuracy and efficiency are achieved and the safe and stable operation of the power grid and electrical equipment is effectively ensured. According to the comprehensive evaluation system, the work efficiency can be greatly improved, massive manpower, materials and financial resources are saved, and the system has great economic and social benefits.