Objective To detect the COMP and aggrecan content in serum of patients with KOA and explore its correlative factors.Methods COMP and aggrecan in serum of 100 patients with knee-osteoarthritis(KOA group)and 30 healthy volunteers (control group)were measured by ELISA.Correlative factors for COMP and aggrecan levels were tested by linear regression analy-sis.Results COMP and aggrecan levels in KOA group were significantly higher than that in control group (P < 0.05 ).Serum COMP and aggrecan levels were positively correlated with age,body mass index(BMI),WOMAC scores and X-ray K-L grade(P <0.05).Conclusion Serum COMP and aggrecan are useful markers in the diagnosis,which their level in KOA are higher than the normal people.Moreover,these rise of levels positively correlated with clinical disease parameters and radiological joint damage.