The present invention relates to method and device for determining Gamma parameters and displaying method for a display. A method for determining Gamma parameters for a display includes: setting brightness of the display; lightening a standard image of gradient tricolor under the brightness; calibrating the displaying of the standard image of gradient tricolor with multiple different Gamma values; obtaining the optimal Gamma parameters for the tricolor based on the calibration results; and storing the optimal Gamma parameters for the tricolor corresponding to the brightness in a display chip. The method for determining Gamma parameters for a display calibrates the displaying of the standard image of gradient tricolor with multiple different Gamma values, which can obtain the optimal displaying results based on different calibration results. The optimal Gamma parameters for the tricolor corresponding to the brightness, which represent the optimal displaying results, are obtained based on the calibration results.