Although most business ethical decisions are made by teams rather than individuals, only a few studies have focused on team ethical decision making, which remain on comparing the results of individual and team ethical decision-making directly without much aid of theories. Based on studies of individual ethical decision-making, group decision-making, and Chinese cultural characteristics (reflection, zhongyong, authoritarian leadership, et al.), we intend to explore the mechanism of team ethical decision making process and the effect pattern of its antecedents. Specifically, it will include four sub-studies in two aspects via multiple methods. First, a process mechanism model is developed to look at the mechanism of team ethical decision-making process. Second, based on social decision scheme theory, an opinion integration mechanism is set up to integrate the opinions out of team ethical decision-making when focusing on the core differences between team and individual ethical decision-making. The other two are about member and leadership with regard to the effect pattern of antecedents: to study the mechanism of how member diversity influences team ethical decision-making via information processing and team conflict; to study the mechanism of how leadership features affects team ethical decision-making by information sampling model.