Abstract: Objective To compare the effectiveness and safety of short axis-out of plane ultrasound guided method and direct palpation method in the radial artery catheterization of patients with atrial fibrillation. Methods A total of 70 patients with atrial fibrillation who underwent cardiac surgery in the First Affiliated Hospital of Nanjing Medical University from June to December, 2020 were enrolled. According to the random number table method, they were divided into two groups(n=35): a short axis-out of plane ultrasound guided (UG) group and a direct palpation (TP) group. Both groups were compared for the first puncture success rate, the first catheterization success rate, the completion rate within 3 min, the overall success rate, the times of catheterization attempts, the numbers of puncture sites, catheterization time, the rate of damage to the posterior wall of the radial artery, the incidence of subcutaneous hematoma during the puncture, and the incidence of subcutaneous ecchymosis on the first day after operation. Results Compared with the TP group, the UG group presented remarkable increases in the first puncture success rate, the first catheterization success rate, the completion rate within 3 min and the overall success rate (P<0.05), decreases in the times of catheterization attempts,the number of puncture site, and catheterization time (P<0.05), and decreases in the incidence of posterior wall damage, subcutaneous hematoma and subcutaneous ecchymosis (P<0.05). Conclusions Short axis-out of plane ultrasound guided radial artery catheterization is safe and effective choice for patients with atrial fibrillation with high success rate, short operation time and few complications.