The utility model discloses a transformer remanence detects and demagnetization device, including alternating current power supply module, power conversion module, DC power supply module, control collection module, frequency conversion pressure regulating unit, human -computer interaction unit, data collection module, intelligent analysis system and testing transformer. Spread into testing transformer remanence content into the intelligent analysis system through data acquisition module, by human -computer interaction unit reads, operating personnel is according to the defeated entry control instruction of remanence content, and the required low -frequency voltage of control frequency conversion pressure regulating unit output is to the testing transformer demagnetization. The utility model discloses when obtaining better erasure effect, dwindled the power capacity and the volume of demagnetization device, make the demagnetization device can satisfy the space requirement of field test condition, leading to analytic system through intelligence and transmitting the unit to human -computer interaction with the real -time remanence surplus of transformer, the magnetic treatment process that disappears can accurate, audio -visually be learnt to operating personnel to with the corresponding control command of this input, in order to reach final thorough demagnetization to testing transformer.