In order to further study the fatigue performance of RD joint, the RD joint was subjected to central loading by simulating wheel loads, and the fatigue life of RD joint under corresponding hot spot stress range was obtained by conducting fatigue tests. The 3D solid finite element model of RD joint in steel bridge decks was established by using ABAQUS. Based on the effective numerical model, the fatigue life of RD joint was compared and analyzed by using the hot spot stress method and the critical distance theory respectively. The results show that under the same finite element mesh, the hot spot stress results obtained by two -point extrapolation and three-point extrapolation are relatively close, while the characteristic stress obtained by point method using the critical distance theory is smaller than that obtained by line method. The evaluation results obtained by FAT90 S-N curve recommended by IIW are too conservative, while the prediction results of FAT125 S-N curve are relatively close to the measured value. Compared with the hot spot stress method, the critical distance theory can get more accurate prediction results, in which the prediction errors obtained by the point method and the line method are 17% and 32% respectively. In general, both the hot spot stress method and the critical distance theory can get relatively conservative fatigue life prediction results. Therefore, the two methods are feasible and safe for fatigue behavior evaluation of typical welded joints in steel bridge decks. However, the point method has higher prediction accuracy and is also more convenient in practical application.