Abstract: The magnetic detector made of aamorphous soft magnetic film cores has better characteristics. Experimental results indicate that the detector has a good linear relation between the double-frequency single voltage output and the magnetic field, a magnetic resolution of 10-10--10-11T, and a temperature coefficient of 0.05%/℃ between －40--120℃, The magnetic resolution of the detector increases with lengthening the core, but it is independent of the width and thickness of the core in a certain range. This kind of detector compared with the detector using polycrystal soft magnetic thin film has many advantages, such as smaller side, better durability, stability and temperature characteristic.