Gain offset gamma model was improved based on linear interpolation method according to CRT display color rendering characteristics. A new model was put forward to precisely control chromaticity and color difference of CRT display, which considered three channels interference each other and the environment brightness influence, and as on. The model was verified by experimental measurement and theoretical calculation. The results showed that average controllable precision of the color of Y, L*, a*, b* of the proposed model is 0.255 4, 0.280 4, 0.072 5, and 0.125 5 respectively; controllable chromatic aberration is 0.350 7ΔE*-ab, which means that the proposed model has more greatly improved control precision than the existing GOG models.