Abstract: Although blood protection technologies such as autologous blood transfusion can alleviate to some extent the short supply of clinical blood, red blood cells are still in great demand as the main blood component. This problem can be solved by the safe production of red blood cells in vitro. At present, mature erythrocytes can be differentiated from embryonic stem cells, human induced pluripotent stem cells, umbilical cord blood, peripheral blood, and immortalized erythroid progenitor cell lines. This article reviews the sources and applications of red blood cells produced in vitro, and analyzes the current challenges, in order to provide new insights for blood transfusion therapy.