A method and a system for enhancing colors of an image are disclosed. The method comprises: converting the color components in an RGB color space of each pixel in an image into a hue component, a saturation component, and a value component in an HSV color space of the pixel; stretching the saturation component when it is greater than 0 and smaller than 1; converting the hue component, the stretched saturation component, and the value component into an enhanced red component, an enhanced green component, and an enhanced blue component in the RGB color space. Through the method, the phenomenon of color shift can be prevented, thus enabling the image to be brighter and vivider. Hence, the viewers' visual experience can be improved. The method can relieve the problems of color shift and picture washout.