Abstract: A new method is proposed for realization of watercolor which is aimed at special texture and complex artistic effects of watercolor.　It is based on pigment diffuse，and it is the most important part of watercolor simulate process.According to the necessary information which the source image provided，the author concentrated on the method of image space processing and actualized two essential special artistic effects of painting techniques（the wet-on-wet and the wet-on-dry painting），such as：edge darkening，pigment diffuse，flow patterns and smooth lighting.In the end，it is integrated paper texture in order that non-photorealistic watercolor be similar to traditional watercolor effect.

Key words: pigment diffuse, realization of watercolor, edge darkening, Non-Photorealistic Rendering（NPR）

摘要： 针对水彩画独特纹理和复杂艺术效果，提出一种新的仿真模拟水彩画的方法，该方法基于颜料的扩散，也是水彩画模拟过程中最重要的一个环节。根据输入原图像所提供的重要信息，运用图像处理的方法，实现了两个最基本的绘制技术（即湿到干和湿到湿的绘制）所表现出的水彩画独有艺术效果，如：边缘暗色化、颜料颗粒扩散、流动图案及平滑光照等，最后加入纸张纹理，使最终产生的非真实感水彩画更加接近于传统水彩画的效果。

关键词: 颜料扩散, 水彩画仿真, 边缘暗色化, 非真实感绘制