Fifteen new absorption lines were observed when studying CO2 absorption spectroscopy by wavelength modulation (WM) technique with a DFB laser. The line intensity we can detect is 2.251 63 x 10(-27) cm(-1) x (moleculecm(-2))(-1) at 6.67 x 10(2) Pa pressure, corresponding to an absorbance of 3. 88 x 10(-8). The overtone spectra of CO2 around 1.31 microm have been measured with a tunable diode laser and the corresponding spectral parameters (positions, intensities, and self-broadening coefficients) are presented.