For the problem of sunlight fluctuation influence on vision navigation in greenhouse environment, a navigation information acquisition method based on illumination chromaticity stability was proposed. By comparing the distribution of navigation line image in different color spaces, a light-color analysis model was established to the processes of navigation detection in variable illuminations. Combination model of g, Cr, Cbcolor components was used to extract guidance line rapidly and effectively. The navigation parameters including lateral deviation and angle deviation were obtained from reference navigation line fitted by an optimized Hough transformation. 150 images with navigation information taken under different light conditions were tested by the recognition algorithm, which can detect navigation line with a right recognition rate of 93.9%. The navigation experimental results showed the average processing time of navigation parameters acquisition was about 95 ms, and the maximum error of path tracking was less than 6 cm with the speed lower than 1.5 m/s, which satisfied real-time requirements of vision navigation. 