Abstract: The social dissemination and communication of science is always an important social function of science. With the coming of mega-science epoch, the communication between science and the public has been growing scarce. However, the social media provide a path for the communication between science and the public, the scientists could also disseminate the scientific achievements direct to the public with the social network platform. As a result, a new scientometrics index takes shape——Altmetrics. This paper takes Proceedings of the Royal Society B-Biological Science and Biology Letters as the object, explores the influence factors for paper ReTweeted on Twitter. From the perspective of time and retweeted users’ factors, we construct the negative binomial regression models to analyze the impacts for retweeting. The result showing that, the published time and delay time have a significant effect to the overall retweeted times the retweeted from the member of public, but the delay time hadn’t make a significant effect for scientists; as while, Journal Public Platform and the retweeted users with many followers also have a significant effect to the overall retweeted times, retweeted from the public and scientists (except the journal public platform for the public). The characteristics of time response and retweeted users’ response reflect the nature of altmetrics——an index for the scientific-social communication.