给出了微分吸收法测量二极管电压的基本原理和实验结果。利用MCNP程序对轫致辐射-衰减-探测器系统建模，模拟得到了输出剂量与二极管工作电压关系拟合曲线。建立了微分吸收法测量二极管电压测量系统，通过在探测器前端放置不同厚度的吸收片，得到了衰减程度不同的波形。结合理论计算的拟合曲线和实验波形，利用迭代法计算得到了晨光号加速器二极管电压，电压峰值为0.58 MV。和传统方法所测得二极管工作电压进行了比较，结果较为一致。

The basic theory and experimental results of measuring diode voltage with differential absorption method were reported. With the MCNP model of “bremsstrahlung-attenuation-detector” system, the relation curve of the radiation dose and the diode voltage was fitted. The measurement system of diode voltage with differential absorption method was established, and the waveforms of diode voltage were gained by putting absorbing films of different thicknesses in front of the detectors. By using the fitted curves and the experimental waveforms, the diode voltage of Chenguang accelerator was obtained through iterative method. The peak value of diode voltage was 0.58 MV. The results derived with differential absorption method agree with those measured with the conventional method.