Unlike most current academic studies on corruption in China, which focus on the theme of how political, economic and social environments have caused corruption at the macro-level, this paper takes a micro-view. It concentrates on the question of how corruption, notably bribery, takes place between a briber and the bribed. Moreover, it examines what exact role guanxi-practice plays in corrupt exchange and, more importantly, why it constitutes a critical element. Through in-depth case-studies derived from extensive fieldwork, this paper comes to the conclusion that the micro-level operation of corruption in China is not due to some haphazard aggregation of sporadic acts but follows certain rules and codes of conduct, which should be seen as an informal institutional mechanism facilitating the contracting process of corrupt exchange. This paper also demonstrates that guanxi-practice embodies such rules and codes of conduct. Such conduct purports to remove the legal, moral and cognitive barriers impeding the contracting process of corrupt exchange by grafting a corrupt agreement upon a social setting, in which risk of exchange safety is controlled, and moral costs and cognitive dissonance are reduced. Therefore, this paper contends that the causality link between guanxi-practice and corruption is the inverse of the view held by many. It is not that the participants of corruption are compelled to corrupt conduct because of the existence of the guanxi-practice, but on the contrary, these participants adopt guanxi-practice as an alternative operating mechanism that facilitates corruption.