In order to improve the inversion precision of CO2 lidar, the fine structure in CO2 absorption spectrum (at around 1.572 m) has been detected accurately, with tunable diode laser absorption spectroscopy (TDLAS) technique in a double beam differential system. Differences between absorption spectra were analyzed. The five kinds of pressure-broadened coefficients and absorption cross sections are obtained respectively at 287, 297, 311, 315 and 324 K. The temperature-dependent exponents of CO2 are also calculated, these parameters would be a series of corrections and supplements for the existing database. These results may help improve the detection capability of CO2 lidar.