Objective To observe the therapeutic effect of lymphatic plasma therapy （LPE） combined with semi whole blood exchange on patients with moderate to severe anemia caused by severe postoperative infection. Methods Thirty patients who developed severe postoperative infections with moderate to severe anemia and were treated with antibiotics for 48 to 72 hours but failed to meet the criteria were divided into an observation group （LPE combined with semi whole blood replacement surgery and antibiotic treatment， n = 15） and a control group （conventional antibiotic anti infection and blood transfusion treatment， n = 15）. Evaluation indicators of infection and anemia between and within two groups before and after treatment， and the treatment effect were compared， respectively. Results There was no statistically significant difference in the observation indicators of infection and anemia between the two groups before treatment （P > 0.05）； After each treatment， there was a statistically significant difference in the evaluation and observation indicators of infection and anemia between the two groups （P < 0.05）； Observation group： There was a statistically significant difference in the observation and evaluation indicators of infection and anemia before and after treatment within the group （P < 0.05）； Control group： Compared within the group before and after treatment， there was no significant decrease in WBC， NEUT， and NEU observation indicators， and CRP and PCT observation indicators showed an upward trend， while RBC， HBG， and HCT did not show a significant increase. The difference was not statistically significant （P > 0.05）； Conclusions The combination of LPE and semi whole blood replacement surgery is superior to the conventional treatment regimen of antibiotics alone for anti?infection and blood transfusion to improve anemia symptoms in the treatment of postoperative severe anemia.