Employee creativity has become one of the determinants that enhance the competitiveness of enterprises. Studies have found that the organizational climate is essential for employee creativity; however, the mechanism through which the organizational climate affects employee creativity is still not well understood. The key to stimulating creativity lies in understanding the mental states of those engaged in creative work. Therefore, intrinsic motivation and mental involvement are both potential mediators of the relationships between organizational climate and employee creativity. An analysis of data obtained from 181 employees in various enterprises of Zhejiang province indicates that a supportive organizational climate is positively associated with employee creativity. This relationship was shown to be mediated by intrinsic motivation and mental involvement. These findings suggest that organizations should pay great attention to the mental states of employees while developing a supportive organizational climate in order to promote employee creativity.