同步辐射光源中的高次谐波会使透射光栅衍射效率标定精度变差。为了校正光源中的高次谐波对透射光栅衍射效率标定的影响,提出了一种光源存在弱谐波情况下的透射光栅衍射效率标定方法,通过使用谐波X射线的衍射效率修正基波衍射效率标定中谐波的影响,从而得到更为准确的透射光栅衍射效率。使用该标定方法在北京同步辐射光源上开展了透射光栅相对衍射效率标定工作。实验结果表明:在100~800eV存在高次谐波能段,修正后透射光栅一级与零级的相对衍射效率与理论模拟结果吻合较好,修正后光栅二级与一级的相对衍射效率更接近理论模拟结果,但与理论模拟结果仍有较大偏差,该偏差主要来源光栅较弱的二级衍射。 High-order harmonics in a synchrotron radiation source will degrade the diffraction efficiency of the transmission grating. In order to correct the influence of the high harmonics in the light source on the calibration of the diffraction efficiency of a transmission grating, a method of calibrating the diffraction efficiency of the transmission grating in the presence of weak harmonics of the light source is proposed. The diffraction of the fundamental wave is corrected by using the diffraction efficiency of the harmonic X-ray The effect of harmonic in the efficiency calibration, so as to obtain a more accurate transmission grating diffraction efficiency. Using this calibration method, the relative diffraction efficiency calibration of transmission grating was carried out on Beijing synchrotron radiation source. The experimental results show that there are harmonic energy segments in the range of 100-800 eV. The relative diffraction efficiency of the first and the zero order of the transmitted grating coincides well with the theoretical simulation results. The relative diffraction efficiency of the second and the first order of the modified grating is more Close to the theoretical simulation results, but there is still a large deviation from the theoretical simulation results. The deviation mainly comes from the weak second-order diffraction of the grating.