This study was purposed to investigate the correlation of deep vein thrombosis (DVT) with C-reactive protein (CRP), fibrinogen (Fg), coagulation factor VIII (FVIII:C), coagulation factor IX (FIX:C) and to explore the effect of inflammation and coagulation as well as their interaction in DVT and its mechanism. 59 patients with DVT undergoing selective venous ultrasonography and 26 healthy individuals as controls were enrolled in this study. The plasma level of CRP was detected by immunoturbidimetry, FVIII:C, FIX:C levels were determined by a one-stage assay and fibrinogen level was measured by full-automatic biochemical apparatus. The results showed that the mean levels of plasma CRP, Fg, FVIII:C and FIX:C were significantly higher in deep vein thrombosis group than that in controls [CRP (2.67 +/- 0.91) vs (0.14 +/- 0.08) mg/dl; Fg (4.73 +/- 1.36) vs (2.79 +/- 0.66)g/L; FVIII:C (126.71 +/- 28.10) vs (81.35 +/- 20.77)%; FIX:C (81.01 +/- 23.60) vs (70.71 +/- 11.3)%] (p < 0.01), and the level of plasma CRP was strongly correlated with Fg, FVIII:C and FIX:C (r(s) = 0.432, 0.571 and 0.544, p < 0.01). It is concluded that the DVT and inflammation are closely related, increased level of plasma CRP may be a predictor of DVT. Increased plasma levels of Fg, FVIII:C and FIX:C all are important risk factors to DVT. Interaction between inflammation and coagulation promote the incidence of DVT, which may be one of DVT pathogenesis.