中红外为分子的基频吸收波段，可被用于痕量气体的高灵敏度检测。介绍了基于中红外室温连续量子级联激光器（CW-QCL）结合波长调制技术（WMS）的光谱检测方法，研究了消除气体间交叉干扰的方法，并进行了相关的验证实验。利用中心波长在1274 cm-1波段附近的量子级联激光器搭建了一套开放光路温室气体探测实验系统，进行101 m开放式测量实验，实现了对大气中CH4、N2O的同步在线测量，检测限分别为3.87×10-9和1.28×10-9，验证了实验系统和实验方法的可行性，为实现区域高灵敏温室气体监测奠定了基础。

The mid-infrared spectrum region, which corresponds to the fundamental absorption of molecules, can be applied to high-sensitivity trace gas measurement. A method using a mid-infrared continuous-wave quantum cascade laser (CW-QCL) operated in room temperature with wavelength modulation spectroscope (WMS) is demonstrated. A method of eliminating influence of cross interference between different gases is studied and related verification experiment is performed. An open path greenhouse gas detection system using a quantum cascade laser with central wavelength around 1274 cm-1 is constructed and utilized to monitor CH4 and N2O in atmsphere simultaneously with a 101 m open optical path measurement test, which achieves detection limits of 3.87×10-9 and 1.28×10-9 respectively. The feasibility of the experiment system and the method is verified, which lays a foundation for high-sensitivity detection of greenhouse gases in regional environment.