The invention discloses a current sensor device and a measuring method based on a TMR tunnel magnetoresistive device. The device comprises a current carrying wire, a TMR sensor, a signal conditioningunit and a temperature sensor; the current carrying wire is used for being connected with a measured current port so as to access a measured current; the TMR sensor is used for sensing a magnetic signal of the current carrying wire through a TMR tunnel magnetoresistive element and converting the magnetic signal into an electric signal; the signal conditioning unit is used for performing signal preprocessing on the electric signal output by the TMR sensor according to a preset rule; the temperature sensor is used for measuring the working temperature of the TMR sensor; the control unit is usedfor receiving the electric signal preprocessed by the signal conditioning unit, and converting the electric signal into a corresponding current signal through the preset rule; and the control unit compensates the electric signal according to the working temperature and a preset compensation model, and finally outputs the current signal.