[Objective] To evaluate the application of controlled hypotension in total knee arthroplasty under general anesthesia.[Methods] A total of 120 patients received knee arthroplasty from January 2019 to December 2020 were randomly divided into control hypotension group and routine group, with 60 patients in each group. The controlled hypotensive group was treated with dexmedetomidine combined with sevoflurane without a tourniquet, while the conventional group was treated with a tourniquet throughout the whole process.Clinical results, intraoperative hemodynamic changes, and changes in laboratory related indicators were compared between the two groups. [Results] The operation was successfully completed in both groups, and the incidence of adverse reactions in the control hypotensive group was decreased (P<0.05).The amount of intraoperative fluid infusion, blood loss and 24h postoperative drainage volume in the controlled hypotension group were significantly lower than those in the conventional group (P<0.05).There were no significant differences in MAP and HR at T1 and T2 in hemodynamic indexes between the two groups (P<0.05).MAP and HR decreased at T3 and T4, and the control hypotensive group was significantly higher than the conventional group (P＞0.05).At T5, HR in controlled hypotensive group was significantly lower than that in conventional group (P<0.05).There was no statistical difference in preoperative laboratory indicators between the groups.Elevated Cr, BUN, Cys-c and decreased GFR were observed in both groups 1 and 24 h after operation.The levels of Cr, BUN and Cys-c in control hypotensive group were significantly lower than those in conventional group (P<0.05);Decreased GFR level in the conventional group was significantly higher than that in the control hypotensive group (P<0.05).[Conclusion] Dexmedetomidine combined with sevoflurane for controlled hypotension in knee arthroplasty has a good effect and has a certain protective effect on the kidney.