Facial expressions exhibit not only facial feature motions, but also subtle changes in illumination and appearance. Since it is difficult to generate realistic facial expressions by using only geometric deformations, the details such as textures should also be deformed to achieve expression that is more realistic. In this paper, we propose a nonlinear model for skin color change and a model-based synthesis method for facial expression. Experimental results show that the proposed method generates realistic facial expressions under various lighting conditions.