Combined with the atmosphere extinction data when the lidar was operated,N2 vibrational Raman scattering signals of detecting atmosphere CO2 Raman lidar system were used to determine the lidar geometric form factor,and analyze and estimate the influence of aerosol wavelength exponent changes on geometric form factor determination. The results show that the aerosol wavelength exponent would have influenced the determination of geometric form factor with vibrational Raman signals. When the aerosol wavelength exponent was determined by other experiments,determination of geometric form factor for Ramon lidar with vibrational Raman scattering signals is simple,convenient and credible.