Abstract: Objective To explore the proper range of negative pressure drainage value of posterior lumbar fusion, and the effect of different negative pressure drainage values on drainage effect.Methods A total of 72 patients who underwent posterior lumbar fusion in the Affiliated Hospital of Xuzhou Medical University from December 2021 to August 2022 were selected. According to negative pressure drainage values, the patients were randomly divided into groups A, B, C and D(n=18), with the negative pressure drainage values of 50, 100, 200 and 300 mmHg, respectively. These groups were compared for their general information, introperative blood loss, drainage volumes at postoperative 6 h, 12 h, 24 h, and 48 h, hemoglobin before surgery and at postoperative 48 h and 72 h, the number of patients requiring blood transfusion and incision complication.Results There were no statistical difference in age, sex, and intraoperative blood loss among the four groups(P>0.05). Each group showed remarkably differences in drainage volume at postoperative 6 h and 12 h(P<0.05).Gronp A and gronp B showed differences in drainage volume at postoperative 24 h and 48 h(P>0.05). The drainage volumes of groups A and B at postoperative 24 h and 48 h were significantly less than those of groups C and D,respectively(P<0.05). Group A presented decreased hemoglobin at postoperative 48 h, compared with groups C and D(P<0.05); without difference in hemoglobin, compared with group B(P>0.05). There were two and five cases of blood transfusion in groups C and D, respectively, and no blood transtusion cases were reported in groups A and B. No statistical difference was found in incision complication among the four groups.Conclusions The negative pressure drainage value of open lumbar postoperative drainage device can be set from 50 to 100 mmHg, which will significantly reduce postoperative drainage volume and total blood loss, and reduce the probability of blood transfusion.