To improve the wavelength calibration accuracy of a solar absolute irradiance spectra-radiometer, a wavelength calibration scheme that a linear CCD was used as position sensor to control the wavelength was presented. The wavelength calibration was implemented from 0.4 μm to 1.0 μm. Based on the install configuration of the instrument and the parameters of Fèry prism, the relationship between wavelength and CCD pixels was described and the calibration and calculation methods were depicted in detail. The selection of devices, the designs of a clock driver and an output signal processor for CCD were introduced. For wavelength calibration in a lab, a tunable laser was used as source, and the relationship between CCD pixels and center wavelength was confirmed and verified by spectral scanning. Furthermore, the outdoor measurement was developed and the results were compared with that of a visible-short wave infrared spectrometer. Experimental results indicate that the precision of wavelength orientation is better than 0.5 nm, and the absorbing peak of spectral curve measured is accord with the absorbing spectra of typical atmosphere exactly. The feasibility of spectral scanning scheme and the reasonability of electronic design of CCD were demonstrated finally.