Abstract: Recently, there are a series of reports focused on Adverse Events following Immunization (AEFI) of HBV produced by a certain company, which has already affected the HBV planned immunization in some area, China. It suggests that vaccine safety become an important factor in our country’s planned immunization against infectious diseases. The reasons and solutions of the problems in vaccine safety in the history of vaccine development were reviewed in this article, in order to show the inevitability and Objective existence of AEFI. In this case, Immunology, including basic theory and techniques, plays a key role in the solution of problems in vaccine safety and to reduce the incidence of AEFI to ensure our country’s planned immunization being in progress and safely.