AbstractSocial media platforms allow rapid information diffusion, and serve as a source of information to many of the users. Particularly, in Twitter information provided by tweets diffuses over the users through retweets. So it is of great significance to study the char- acteristics of retweets for marketing and outbreak detection. In this paper, we present a hypothesis that the frequency distribution of retweets follows a power law distribution asymptotically by analyzing the retweets data. Then, we propose a method to model the mechanism of retweet under considering preferential attachment and transmissibility of tweets. We quantify the parameter and get a power law distribution, the simulation results and the results of data analysis are proved to be consistent, so the model can explain the behavior of retweets.