为了适应当下网格化大气监测中低体积分数的SO2气体检测需要，针对紫外荧光法模块化应用的光路关键性问题，将物远心光学系统与双平凸组合光学系统相结合，应用于SO2检测模块的激发光路和采集光路上。采用多光学系统优势互补的方法，进行了理论分析和实验验证。通过模型的建立，分析了光路系统对反应室信噪比的影响，结合ZEMAX软件仿真、蒙特卡洛法公差评价分析与整个光学系统的间接实验验证，取得了该优化光路系统应用。结果表明，其仪器线性度的相关系数的平方能够达到0.9999。该光学系统具有较强的应用价值，能够为紫外荧光法模块化光路系统设计提供理论依据与实验数据支持。

In order to meet the requirement of low volume fraction SO2 gas detection in grid atmospheric monitoring, aiming at the key problem of optical path in modular application of ultraviolet fluorescence method, object telecentric optical system was combined with double-plane-convex optical system to apply the excitation and acquisition paths of SO2 detection module. Theoretical analysis and experimental verification were carried out by complementary advantages of multi-optical systems. Through the establishment of the model, the influence of optical system on signal-to-noise ratio of reaction chamber was analyzed. Combining ZEMAX software simulation, Monte Carlo tolerance evaluation analysis and indirect experimental verification of the whole optical system, the application of the optimized optical system was achieved. The results show that, the square of correlation coefficient of instrument linearity can reach 0.9999. The optical system has strong application value. It can provide theoretical basis and experimental data support for the design of modular optical system of ultraviolet fluorescence method.