Abstract: The author proposes that the partially prestressed highway bridges be designed according to the degree of prestresing. In this paper, the design method and its merits are explained. The calculations for the projects in the "Standard Design Drawings JT/GQB 025-75" has been made. Based on this, the influence of the degree of prestressing upon the steel requirement and the relations between the degree of prestressing and the crack width have been analyzed. The crack control by hypothetical tensile stress is too conservative and unsuitable for lower degree of prestressing. Therefore, the recommendation for design of PRC bridges by means of hypothetical tensile stress is improper.