The conflict between self-interest and the interests of others is assumed to be one of the key conflicts involved in social decision-making. The trade-off between self-interest and the interests of others becomes pivotal. In classical western economic theories, pursuing material self-interest was assumed to be the sole motivation of people. This assumption has been challenged recently in the field of Developmental Psychology, Comparative Psychology, Economic Psychology, Behavioral Economic, and Neuroeconomics. It is established that people also concern others’ welfare. The concurrence of pursuing self-interest and concerning the interests of others brings about the problem how people consider the equilibrium between them. Several important conceptions, such as proself behavior, strategic other-regarding behavior, prosocial behavior, cooperation, altruism, reciprocity, fairness and so on, involves the trade-off between self-interest and the interests of others. However, previous theories failed to integrate all these miscellaneous conceptions. In this review, self-interest and the interests of others were constructed as two sides of the equilibrium involved in social decision-making. Through the construction, such important conceptions involved in social decision-making behavior such as proself behavior, strategic other-regarding behavior, prosocial behavior, cooperation, altruism, reciprocity, fairness and so on, were integrated into one framework. The concept of fairness means considering self-interest and the interests of others to the same extent. The concept of proself means considering self-interest more than the interests of others. The concept of strategic other-regarding means strategically consider others in order to pursue self-interest. The concept of altruism means sacrificing self-interest to benefit others. The concept of cooperation means considering the interests of both sides simultaneously. The concept of reciprocity means sacrificing self-interest to benefit others in the first time, and get a pay back in the next time. Theories and empirical findings of each conception were discussed. In conclusion, under the construction of self-interest and the interests of others as two sides of the equilibrium, important conceptions such as fairness, cooperation and so on involved in social decision-making could be integrated into one unambiguous framework.