A prototype of Raman lidar first developed by Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, for monitoring lower-tropospheric CO2 profiles in China is introduced. An ultraviolet laser with wavelength at 355 nm is selected as light source and a photon-counting card is used to acquire atmospheric N2 and CO2 Raman backscattering signals. Methods of the Raman lidar system calibration are analyzed in detail and Li7500 H2O/CO2 analyzer is employed to contrast with our lidar. The results show good agreement in the trend of changing and verifying high detection sensitivity and accuracy of the lidar system. By linear fitting, the calibration error is smaller than 0.2% and 1.5% in horizontal and vertical direction, respectively. Then profiles of atmospheric CO2 can be calculated in accordance with calibration equations and typical measurement results in the western suburbs of Hefei are given. The detection range can reach 2.0 km and 2.5 km in horizontal and vertical direction, respectively.