CO2 as the most important greenhouse gas effecting climate change, inversion accuracy within 1% is essential requirement in climate research. One of key points to improve CO2 retrieval precision is account for atmospheric scattering in inversion processing. The spectral range of greenhouse gas monitoring satellite generally is narrow to achieve excellent spectral resolution. High spectral resolution has high sensitivity in CO2 concentration changing, however, traditional differential optical absorption spectroscopy (DOAS) methods are hard to assure accuracy in scattering atmosphere. Aim to meet inversion algorithm development, the influence of scattering in CO2 retrieval from path length is studied, compared with traditional DOAS method in desert and meadow. Result indicates that path length method can improve retrieval accuracy and obtain precision close to 1%, and correlation and dispersion of inversion results also can achieve improvement. It is implied that path length method is capable of reducing the impact due to atmospheric scattering in CO2 retrieval.