Abstract: ?In order to realize control of suitable feed quantity and decrease breakage and lose rate，feed density should be obtained firstly. According to RGB color image spectral analysis of rice, 2R+G color feature parameters were used as the feature of feed density of combine. Functional relationships between 2R+G color feature parameters and actual feed density was established. Results showed that fitting curves were obtained to the remarkable level by the differences of variety and growth period. Feed density of the correlation coefficient of all models was higher than 0.88. This method can provide references to the control of feed quantity.