There is no authoritative data to show whether the fat survival rate of the posterior thigh is high or not, from clinical experience, the fat survival rate of the posterior thigh is generally 30%~50%. The fat survival rate of the posterior thighs should be judged according to the quality of the fat. If the fat density and viscosity of the thighs are good, and the fat purity is high, the fat survival rate is higher, generally at 30%~50%. If the fat in the back of the thigh contains more impurities or the fat purity is not high, the patient’s autologous fat survival rate after fat grafting is generally not high and may be lower than 30%. The fat survival rate of the posterior thigh fat is related to the quality of the fat, and patients with high quality fat have a relatively high fat survival rate after fat grafting. It is recommended that after fat is extracted from the posterior thighs for autologous fat grafting, regular review is needed, and localized lipofilling should be performed several times if necessary.