The objective of this study was to find a new parameter to monitor bleeding tendency after dabigatran etexilate (Pradaxa) medication in Chinese nonvalvular atrial fibrillation patients. Blood samples of 231 nonvalvular atrial fibrillation patients were collected and five routine coagulation examinations (prothrombin time/International normalized ratio, activated partial thromboplastin time, fibrinogen assay, thrombin time and D-dimer) were assayed. After dabigatran etexilate administration, prolonged activated partial thromboplastin time and thrombin time were observed, especially TT. Derived parameter ΔTT (TT after dabigatran etexilate medication – TT before dabigatran etexilate medication) of bleeding patients was higher than nonbleeding patients (97.7 vs. 85.6 s, P = 0.038). When using ΔTT to distinguish patients with and without bleeding events, the cutoff value was 97.25 s, where sensitivity was 82.4% and specificity was 50.0%. The area under the curve was 0.786. TT is better than other routine coagulation parameters in monitoring the effect of dabigatran etexilate. ΔTT can distinguish bleeding patients from nonbleeding patients.