This paper presents a logical framework for negotiation based on belief revision theory. We consider that a negotiation process is a course or multiple courses of mutual belief revision. A set of AGM-style postulates are proposed to capture the rationality of competitive and cooperative behaviors of negotiation. We first show that the AGM revision and its iterated extension is a special case of negotiation function. Then we show that a negotiation function can be constructed by two related iterated belief revision functions under a certain coordination mechanism. This provides a qualitative method for constructing negotiation space and rational concessions. It also shows a glimpse of how to express game-theoretical concepts in logical framework.