Objective To investigate the value of D-dimer in the early diagnosis of idiopathic venous thromboembolism. Methods We detected D-dimer and fibriogen levels in 62 hospitalized patients without history of thrombosis and 62 hospitalized patients with the idiopathic venous thromboembolism. Univariate analysis of the correlation between the D-dimer and fibriogen level and the idiopathic venous thromboembolism was performed. We used D-dimer＞0.5mg/L and fibriogen＞4.0g/L as the cutoff value to calculate the value of early diagnosis of idiopathic venous thromboembolism. Results The univariate analysis showed that the D-dimer and fibriogen levels were both higher in the thrombosis group than in the control group (P＜0.05). With fibriogen＞4.0g/L as the cutoff value, there was significant difference between the thrombosis group and the control group (P=0.00); the sensitivity was 89.29%; the specificity was 56.63%; positive predictive value was 40.98%; negative predictive value was 94.00%. With D-dimer＞0.5mg/L as the cutoff value, there was significant difference between the thrombosis group and the control group (P＜0.05); the sensitivity was 92.31%; the specificity was 96.61%; positive predictive value was 96.77%, negative predictive value was 91.94%. Conclusion Compared with fibriogen＞4.0g/L, D-dimer＞0.5mg/L has better performance for early diagnosis of idiopathic venous thromboembolism. By combination with the other clinically relevant factors, it may contribute to the early diagnosis of idiopathic venous thromboembolism.