Abstract: Objective To analyze the coagulation indexes, biochemical indexes and occurrence of venous thrombosis in patients with heart failure and atrial fibrillation. Methods A total of 86 patients with chronic heart failure were selected and divided into control group(heart failure group)and study group(heart failure combined with atrial fibrillation group)according to whether they were complicated with atrial fibrillation. Cardiac function grading and coagulation indicators such as prothrombin time(PT), activated partial thromboplastin time(APTT), D-dimer were compared between the two groups, and biochemical indicators such as hematocrit(Hct)and C-reactive protein(CRP), and brain natriuretic peptide(BNP)were compared. Besides, the incidence of venous thrombosis in both groups was compared. Results There was no significant difference in ratio of patients with grade Ⅱ of heart function between the two groups(P>0.05); the study group had lower ratio of patients with heart function grade Ⅲ than the control group, and higher ratio of patients with heart function grade Ⅳ than the control group(P<0.05); The levels of PT, APTT and D-dimer in the study group were higher than those in the control group, and the differences were statistically significant(P<0.05). The Hct, CRP and BNP levels of the study group were significantly higher than those of the control group(P<0.05). The incidence of venous thrombosis in the study group was 34.88%, which was significantly higher than 16.28% in the control group(P<0.05). Conclusion The incidence - of venous thrombosis, levels of coagulation indicators and biochemical indicators are higher in patientswith heart failure and atrial fibrillation compared to those with heart failure. Therefore, sufficient attention should be paid during clinical treatment.