Abstract: The Accurate calculation of stress for thin-walled deep beams is a complex mechanical problem. Based on the previous studies, formulas for computing stresses of deep beams with I section subjected to different support restraints and load distributions are obtained by using the semi-inverse method in elastic mechanics and reasonable dimensionless parameters, and bending-shearing coupling is also considered. The analysis of dimensionless warping normal stress indicates as follows: a stronger support restraint leads to larger warping normal stress; the larger change rate of a linear load leads to larger warping normal stress. The values of normal stresses of thin-walled deep beams are always larger than those obtained by pure bending theory of slender beams in material mechanics. This will cause unsafe engineering design. Therefore, the warping stress should be considered in the design and strength checking for deep beams.