Immunization with an HIV vaccine may be the most effective way to stop the HIV transmission epidemic, but to date no effective vaccine has been found to prevent HIV transmission. Due to the fact that HIV viruses can be integrated in the genome of infected cells, causing persistent infection, and the severity of the clinical consequences of AIDS, attenuated and inactivated HIV vaccines are potentially risky for humans and cannot be practically applied as vaccines. The current direction of HIV vaccine research is focused on genetically engineered subunit vaccines, viral vector vaccines and peptide vaccines, but due to the high variability of HIV viruses, the high variability among HIV subtypes, and the lack of suitable animal models, no successful HIV vaccine has been released yet.