针对氨气(NH3)和二氧化硫(SO2)气体吸收谱线在196~214 nm 波段区域存在谱线重叠的问题，在采用傅里叶变换的差分吸收光谱法测量气体浓度基础上，采用分波段方法，解决NH3 和SO2 特征频谱相互串扰对测量的影响，采用非线性修正方法，解决在SO2 高浓度情况下出现的非线性吸收对NH3 气体测量的影响，采用经验模态分解(EMD)降噪处理方法，提高信噪比，最终实现对NH3和SO2气体浓度的同时准确测量。实验结果显示，NH3各个浓度测量误差均在±0.15 mL/m3以内，相对误差不超过±1.5%，最低可探测浓度为1.5 mL/m3；SO2各个浓度测量误差均在±2 mL/m3以内，相对误差不超过±1%，最低可探测浓度为16 mL/m3。

For the overlap of the absorption spectrum of NH3 and SO2 from 196 nm to 214 nm, based on differential optical absorption spectrometry and fast Fourier transform to measure concentration of gases, a method that detecting these two gases simultaneously at two wave length bands is proposed. The crosstalk effects between the characteristic spectrum of NH3 and SO2 are solved. The interference of SO2 to NH3 which is caused by the nonlinearity of the absorption of SO2 with the increase of its concentration within 196~214 nm wavelength band is corrected, then the real concentration of NH3 are obtained. The signal to noise ratio is improved by empirical mode decomposition (EMD) noise reduction method. The measurement error of NH3 concentration is within ± 0.15 mL/m3 , ang the relative error is less than ±1.5%. The detectable concentration limit is 1.5 mL/m3. For SO2, the measurement error is within ±2 mL/m3, and the relative error is less than ±1%. The detectable concentration limit is 16 mL/m3.