Based on the giant magneto-impedance principle of amorphous materials,a novel magnetic sensor is presented and developed.According to double peaks feature of the amorphous,the working principle is ana-lyzed.The sensor structure with closed loop negative feedback is designed,and the mathematical model of the sensor is deduced.By analyzing the error transfer function of the sensor,PI controller is proposed,which can e-liminate the steady state error and improve the linearity.The experimental results show that the performance of the sensor is improved by PI controller.The linearity is within 0.2%and the sensitivity is up to 1.759 V/Oe.