In contrast to the individual and nonsocial organism view of bacteria, recent discoveries show that bacteria can communicate and exhibit population behaviour via a system known as quorum sensing. Some bacterial behaviour can only be initiated when the cell number reaches a certain level (Quorum sensing, QS). It is generally believed that quorum sensing is used to coordinate cooperative behaviours at the population level; however, many issues exist regarding the evolution or development of such a system. In the present paper, the evolutionary process of bacterial quorum-sensing systems is discussed based on recent events and progresses in this field. As quorum sensing systems are often affected by environ-mental factors, such as temperature, pH, and nutrient levels, it is hence proposed that the evolution of bacterial cooperation, such as the quorum sensing, is rather a dynamic and ever-changing process which is radically affected by environmental conditions, genetic exchanges, as well as by changes in microbial community. The dynamic transformation suggests the advantages of cheaters of the system might have been short-lasted and confined in certain conditions and diminish over a long run.