波荡器磁中心轴的标定是保证自由电子激光装置波荡器安装准直精度的重要前提。介绍了一种利用磁靶标实现波荡器磁中心高精度标定的方法。设计制造了由若干块永磁块组合构成的磁靶标，其能产生一正一斜两个高梯度四极场。测出了两四极场垂直分量的零点位置分布并依此给出了磁靶标的具体使用方法。结果表明：标定后的波荡器磁中心在磁靶标坐标系中水平方向测量精度好于±20 μm，垂直方向测量精度好于±2 μm。

The undulator magnetic fiducialization is an important prerequisite to ensure the undulator segments’ installation precision of the FEL device. A device called “magnetic landmark” was developed to achieve high precision undulator magnetic fiducialization. The landmark consists of several permanent magnets which can generate a normal and a skew quadrupole field with high gradient in two orthogonal directions. Positions of the zero point of the two quadrupole fields’ horizontal component were measured and the specific use of the landmark is given. The results show that the accuracy of the magnetic center axis of an undulator after fiducialization in the landmark coordinate system is better than ±20 μm in the horizontal direction and ±2 μm in the vertical direction.