Abstract: Inter-pregnancy interval (IPI) usually refers to the interval between the previous live birth and the next conception. It not only affects the fertility level and the long-term balanced development of population in a country or region, but also has adverse effects on maternal and child health if IPI is too long or too short. At present, under the background of China’s “three-child policy”, the issue of female IPI has become particularly important. This paper reviews the definition, status, factors associated with IPI, the impact of different IPI on maternal and infant health, and the appropriate IPI, in order to provide scientific evidence and theoretical support to prepare women for conception scientifically.