在分析现有表面缺陷检测方法特点的基础上,提出了开放磁路检测原理与方法.在磁铁与试样之间构建一个开放磁场,试样表面存在缺陷时,会引起开放磁场分布的变化,通过传感器获得磁场的变化以获得试样表面缺陷的相关信息.详细研究了开放磁路特征参数对检测信号的影响以及盲孔检测时的量化特征.由于该检测方法对磁化强度基本上没有要求,从而有更广泛的应用. On the basis of analyzing the characteristics of the existing surface defect detection methods, an open magnetic circuit detection principle and method are proposed. When an open magnetic field is formed between the magnet and the sample and the surface of the sample has defects, the open magnetic field distribution will be changed, The change of the magnetic field is obtained by the sensor to obtain the relevant information of the surface defects of the sample.The influence of the characteristic parameters of the open magnetic circuit on the detection signal and the quantification characteristics of the blind hole detection are studied in detail.Because the detection method basically does not require the magnetization, Which has a wider range of applications.