The form of corruption evolves in the continuous games with anti-corruption. With the change of institutional environment caused by corruption, a salient symptom of corruption in current China is its fission: corruption spreads from individuals to groups and then to the whole organization, from lower-level administrators to higher-level leaders according to the managerial logic. In essence, corruption fission is an on-going process during which the corrupt actors produce and reproduce the corruption networks by committing illegal interest exchanges. This article develops a social exchange analysis to this phenomenon and attempts to answer two basic questions: why and how corruption in China takes on a form of fission. Social exchange theory integrates and complements to some extent the rational choice perspective, the organizational institutional perspective and the social network perspective, providing a relatively complete theoretical framework to explain the dynamics and tactics underpinning the corruption fission. Two main dynamics have been identified, namely the internal dynamic and the external dynamic. Specifically, the internal dynamic, regarding the corrupt actors as the fission initiators, demonstrates that they tend to embed themselves into the multi-level corruption networks by seeking for the cover-up and assimilating the immediate colleagues, so as to establish offensive and defensive alliances to make their illegal exchange safer. By contrast, the external dynamic, seeing the corrupt actors as the diffusion receivers, indicates that those who are embedded in the family or acquaintance networks and restricted by the ethical norms of quanzi, e.g. responsibility and renqing, tend to adopt a view of exceptionalism to maintain and expand the improper interest of the quanzi members. To realise the corruption fission, however, it also needs multiple tactics to effectively couple the above two dynamics. The corrupt actors adopt differing exchange tactics based on the stage characteristics of the corruption fission. The corruption fission consists of four stages, i.e. choosing the exchange actors, investing in the exchange relationship, balancing the exchange power and finally establishing the exchange order. Therefore, corrupt actors choose the corrupt exchange parties through risk assessment and tentative social exchange tactics, enter into the “my family” quanzi through simulant-intimate and service penetration tactics and enhance the awareness of interest community through coexistence tactics. A corrupt exchange order is the result of the comprehensive use of those tactics. This micro social order generates self-support norms and logics, which, in turn, facilitate the institutionalization of the corruption fission. To curb the corruption fission in China, it requires integrated measures. Firstly, it hinges on the perfection of the power restriction and supervision system that aims to avoid overconcentration of power and secure the publicity of decision-making. Secondly, we must enhance the corruption cost and implement the consistent punishments on the briber and bribee. Thirdly, the rule of law should be promoted to prevent the permeation of kinship and renqing to the public power area.