Objective:To investigate the relationship between serum levels of cystatin C(Cys C)and and venous leg ulceration(VLU). Methods:Subjects were divided into three groups,chronic venous insufficiency(CVI) patients without ulcers,patients with VLU and normal subjects. Enzyme-linked immunosorbent assay(ELISA) was used for detection of plasma TNF-α,IL-1β,IL-2R,Cys C levels and Cys C level of venous tissue. Results:① The plasma levels of TNF-α and IL-1β in the VLU patients with venous ulcers were(185.46 ± 20.90) pmol/L and(100.60 ± 17.43) pmol/L respectively,and was significantly higher than those in the control group [(32.28 ± 7.76) pmol/L of TNF-α and (58.72± 16.20) pmol/L of IL-1β](P < 0.05). The plasma levels of TNF-α and IL-1β in the CVI without ulcers group were(41.68 ± 7.35) pmol/L and(65.36 ± 25.51) pmol/L,and had no significant difference compared to the control group (P > 0.05);The plasma IL-2R levels in the VLU group and CVI without ulcers group were (138.56 ± 78.75) pmol/L and(94.45 ± 35.26) pmol/L,and both of them had no significant difference compared to the control group[(93.67 ± 12.28) pmol/L](P > 0.05);②Cys C expression in venous tissue was significantly lower in VLU patients than in the CVI without ulcers and control group(P < 0.05);The plasma Cys C level of VLU group was significantly lower than that of control before surgery (P < 0.05),and the plasma Cys C level of VLU group four days after surgery was significantly higher than that before surgery(P < 0.05). ③ The correlation analysis showed that Cys C expression was significantly negatively correlated with expressions of TNF-α and IL-1β(r = -0.878 and -0.990,P <0.05). ④After surgery,ulcer recurrence rate in patients with low expression of Cys C were higher than that with the high Cys C expression. Conclusion:Cys C expression is closely related to the incidence of VLU. Low expression of the Cys C may be an important factor of the incidence and recurrence of VLU.