High spectral resolution solar radiometer for ground-based measurement of atmosphere CO2 absorption spectrum is suggested, including a brief introduction of instrument design, method of relative spectral radiance measuring, calibration of spectrum and instrument line shape (ILS). It is indicated that in the spectral band between 1560 nm and 1575 nm, the spectral resolution of instrument is 0.097 nm, and the relative intensity of stray light is about 0.5%. For instrument validating, CO2 absorption spectrum of experiments are compared with those of theoretic calculation by LBLRTN software. Comparison shows that the relative intensity, wavelength position and shape of those two absorption spectrums are accordant.