Abstract: Objective To evaluate the changes of HCT,HGB and hidden blood loss in the patients with femoral intertrochanteric fracture before and after the treatment. Methods We conducted a retrospective analysis of the cases data of the aged patients with femoral intertrochanteric fracture from January,2013 to December,2015,built a database with EpiData and calculated the hidden blood loss with Gross equation.The changes of HCT and HGB were analyzed with t test. Results According to inclusion criteria,33 cases entered the database,with 91.52 ml average blood loss during operation.The average HCT mean of 33 cases was 33.34±4.79 before surgery,followed by the lowest (26.53±4.49) on the third day after surgery and then it tended to increase.On the third day after surgery,The hidden loss blood in 33 cases was the highest(790.25 ml,92.10%).There were statistical differences between HCT before operation and those on the first day,third day,fifth day,seventh day after operation in transfusion group(P<0.05).There were statistical differences between HCT before operation and those on the first day,third day,fifth day,seventh day after operation in no-transfusion group(P<0.05).There were no statistical differences between HCT before operation,on the third day,fifth day,seventh day after operation in transfusion group and those in no-transfusion group.There was statistical difference between HCT on the first day after operation in transfusion group and that in the non-transfusion group(P<0.05).There were statistical differences between HGB before operation and those on the first day,on the third day in transfusion group(P<0.05).There was no statistical difference between HGB before operation and those on the fifth,on the seventh day after operation.The differences were statistically significant(P<0.05) between HGB before operation and those on the first day,third day,fifth day,seventh day after operation in no-transfusion group(P<0.05).There were statistical differences between HGB in the transfusion group before operation and on the first day after operation and those in no-transfusion group(P<0.05).The differences were not significant between HGB in transfusion group on the third,fifth,seventh day after operation and those in the no-transfusion group. Conclusion The record of hidden blood loss of elderly patients with femoral intertrochanteric fracture should be closely monitored in the clinical work together with HGB,HCT value changes,especially on the third and fifth day after operation.We should estimate the hidden blood loss and perioperative blood loss and then give them corresponding treatments.