Objective To explore the efficacy and safety of different Wafarin anticoagulation intensities in preventing thromboembolism in patients with paroxysmal non-valvular atrial fibrillation (PAF). Methods The patients with PAF were enrolled and divided into four groups. The patients were treated by different Wafarin anticoagulation intensities. The values of the control of international normalized ratio (INR) were 1.3-1.6 in Group 1, 1.7-2.0 in Group 2, 2.0-2.5 in Group 3, and 2.6-3.0 in Group 4. Main destination events, secondary destination events, main bleeding events, secondary bleeding events, main events (main destination events + main bleeding events), secondary events (secondary destination events + secondary bleeding events), and total events (main events + secondary events) were observed and compared in the four groups, respectively. Relevance between events of thromboembolism as well as bleeding and INR was analyzed. Results A total of 868 patients with moderate-high risk PAF were enrolled, and 826 patients (167 cases in Group 1, 220 cases in Group 2, 215 cases in Group 3, and 224 in Group 4) were included in final analysis. The follow-up results showed that the increase of INR led to a reduction in the destination events (there were significant differences between Group 1 and Group 2, 3, and 4 with Plt;0.05), but the bleeding events tended to rise. In terms of the incidence of main events, secondary events and total events, Group 1 was higher than Group 2, 3, and 4 with significant differences (Plt;0.05), except that the main event incidence of Group 1 was not significantly different from that of Group 4 (Pgt;0.05). Conclusion For Chinese patients with PAF, anticoagulation intensities of Wafarin with INR 1.7-2.5 can reduce the destination events with no rise in bleeding events. The anticoagulation intensities within this extent are safe and effective