Abstract: In order to design a high resolution and high sensitivity amorphous wire magnetic sensor based on giant magneto-impedance,through heat treatment of amorphous wire material,design of amorphous wire probe,circuit design and device selection,an amorphous wire magnetic sensor with resolution up to 2 nT and sensitivity of 1608 mV/Gs was developed. The experimental results show that improving the heat treatment method of amorphous wire material and probe design of amorphous wire and optimizing excitation,detection and filtering circuits and device are important means to improve the resolution and sensitivity of amorphous wire magnetic sensor based on giant magneto-impedance.