The study aims to explore the response of the consumers to the retailer's environmental sustainability and its influence on the consumers' perception of the retailer's environmental legitimacy. From the view of the consumers, this paper builds the conceptual model concerning the influence of the retailer's environmental sustainability on the consumer support by setting environmental legitimacy and consumer confidence as the mediating variables. Based on questionnaire investigation, this paper also conducts empirical test by Hierarchical regression and Bootstrap. The study shows that: firstly, the retailer's environmental sustainability exerts a significant positive effect on consumer support as well as environmental legitimacy and consumer confidence; secondly, environmental legitimacy and consumer confidence act as the chained mediating variable in terms of the study on the influence of the retailer's environmental sustainability on consumer support; thirdly, there exist three intermediary paths between the retailer's environmental sustainability and the consumer support: that of environmental legitimacy, of consumer confidence and the chained intermediary path of the environmental legitimacy & consumer confidence, among which the last is more effective in improving the consumer support. These discoveries offer new thought for retailers to increase the consumer support.