To fulfill the right tone reproduction for line-drawing of this thesis, a Non-Photorealistic Rending approach which was bright and dark paint was adopted to introduce the quality factor into line-drawing that reflected the relationship between the brightness and darkness of the input and the density of the printed image. A set of automatic drawing system of line-drawing was established and the right tone reproduction for line-drawing was found out. It can be seen, to show deep feelings, it is also very important to select the appropriate tone reproduction even if it is very little gray numerical segment of bright and dark tone.