To figure out the distribution of temperature gradient along the girder height of steel-concrete composite box girder,combined with the mechanical characteristics of prestressed concrete composed box girder with corrugated steel webs,the calculation formulas of cross-sectional temperature stress along the span in a simply-supported beam bridge with composite section were derived under the conditions of static equilibrium and deformation compatibility of the beam element.The methods of calculating the maximum temperature stress value were discussed when the connectors are assumed rigid or flexible.Theoretical and numerical results indicate that the method proposed shows better precision for the calculation of temperature self-stress in both the top and the bottom surfaces of the box girder.Moreover,the regularity of temperature stress distribution at different locations along the girder span is that the largest axial force of the top or the bottom plate of the box girder is located in the midspan and spreads decreasingly until zero at both supported ends,and that the greatest longitudinal shear density in steel-concrete interface appears at both supported ends and then reduces gradually to zero in the midspan.