For materials such as steel,concrete performance on the spatial variability and non-uniformity problem,considering the reliability theory to uncertain factors as the research object,which can better to simulate the actual stress distribution of components. Getting preferable reinforcement calculation scheme will be useful to put forward the reinforcement method based on reliability theory applied to the optimization of beam design. The results show that the algorithm based on reliability theory is better than conventional algorithm to save the material consumption. The results obtained by the standard formula test meet the design requirements and can provide a reference for practical engineering design.