The color feature of the colorful images is the important characteristic for images analysis; it is an important step to extract the color feature for images analysis. Multidimensional vector space is used in the colorful images and multiple color types are usually referred. A method of Multi-threshold image segment is introduced in this paper. It can transfer the colorful feature into gray image. It is very easy to find and analyze corresponding color feature in the same gray image. The experiments on 200 automobile realistic RGB colorful vehicle license plate images that are taken under various conditions from traffic stops to use the Multi-threshold image segment method show the accuracy of 98%.