Due　to　a　simpler　calculation　process　and　better　precision,　the　rotating-angle　softened-truss　model　is　often　used　to　predict　behaviours　of　reinforced　concrete　shell　or　panel　structures.　In　the　current　algorithm　of　the　rotating-angle　softened-truss　model,　the　calculation　process　is　from　strains　to　stresses,　which　needs　a　trial　and　error　procedure.　A　new　algorithm　of　the　rotating-angle　softened-truss　model　is　proposed　in　this　paper　The　Poisson　effect　is　included　in　the　new　algorithm.　Its　calculation　process　is　from　stresses　to　strains.　The　trial　and　error　procedure　is　avoided,　which　simplifies　the　calculation　process　significantly.　The　reliability　of　the　new　algorithm　is　verified　by　test　data　of　six　panels.