Abstract: A method of detection traces of ferromagnetic material based on an integrated linear Hall sensor was introduced. Different from the traditional NDT different imaging technology, the proposed measurement method is measuring magnetic field of ferromagnetic material surface and reading information of the traces of ferromagnetic material surface by Hall sensor. The experimental showed that the method is effective. Using Hall sensor array could develop the method and the measurement area could be enlarged and the efficiency of scanning could be promoted. This method has a broad application prospect.