Abstract: The fatigue failure mode and mechanism of beam-to-girder joints of H-shaped steel reinforced concrete (SRC) were analyzed based on fatigue experiment. Parameters affecting fatigue strength of the composite joints were discussed and the fatigue strength of the joints was evaluated. Results indicate that the fatigue failure of an SRC beam-to-girder joint occurs in the secondary beam section connected to the main girder. Fatigue fracture of the tension flange of H-shape steel in the secondary beam was the critical attribute for the fatigue failure of the composite joints. A calculation method, easy and practical, was proposed for assessing the fatigue strength of the beam-to-girder joints. This method uses the stress range of tension flange of H-shape steel in the secondary beam and the corresponding S-N curves in national or international codes and standards for fatigue design of steel structures.