Abstract: In this study, under investigation is a propagation system of mobile phone virus via., epidemic model (SEIR model). Via., symbolically computation, an analytic solution for the system is obtained which has higher accuracy and can describe the propagation more completely than those in the previous results. Moreover, several propagation situations on the system are illustrated and figures are plotted for understanding the propagation mechanism based on the obtained solutions. Results of this study might be helpful for the future development of some diffusion in the modern social network, such as online review and user generated contents.