Based on Jones’s moral intensity theory and gray marketing, this paper empirically tests the dimension structures of moral intensity, the impact of moral intensity on the gray-marketing decision making，and the interaction effects of moral intensity dimensions from the seller’s standpoint. This study comes to the following conclusions: Moral intensity can be divided into six dimensions, five of them having direct effects on ethical judgment in addition to the probability of effect and four of them having direct effects on gray-marketing intention except magnitude of consequences and concentration of effect. The interactions between social consensus and probability of effect, proximity, concentration of effect influence the moral judgment，and the interaction between social consensus and temporal immediacy affects the gray-marketing intention. Finally, ethical judgment influences the intention of gray-marketing behavior.