More than a third of the world's population has been infected with hepatitis B virus(HBV) and it is estimated conservatively there are 350 million people who are persistent carriers of HBV worldwide.The prevention and treatment of this infection is the present focus of the society and is the most important task in the medical fields.Based on Nowak model,a model for HBV infection with delay in immune response is built.By analyzing the kinetics of this model and applying Routh-Hurwitze theorem and Lyapunov-Lasalle theorem,the stability of equi...