Nowadays, facial expression synthesis is widely used in  expression  simulation,  recognition  and  animation.  Texture feature  (wrinkle)  after  face  deformation  largely  reflects  the genuineness of the synthesized expression, whose mapping is a critical  step  to  the  expression  synthesis  application.  However, current lighting ratio based wrinkle mapping is sensitive to small source lighting and large lighting difference. In this work, a novel wrinkle mapping based on lighting difference fitting is proposed to improve the genuineness and robustness of mapped wrinkles. Experimental results on expression synthesis with large lighting difference show that the proposed algorithm is competitive on synthesizing visually genuine expressions.