The invention discloses an external scaffold intelligent design method based on BIM, and belongs to the field of buildings, and the method comprises the following steps: step 1, determining external scaffold design parameters; step 2, establishing a material component information base; step 3, reading the CAD elevation of the building structure; step 4, building a building structure model; step 5,inputting design parameters of the outer scaffold; step 6, parameter calculation, design and checking; And seventhly, the formwork is intelligently designed. According to the BIM-based external scaffold intelligent design method provided by the invention, the current traditional engineering structure analysis can be thoroughly changed; According to the low-efficiency mode of CAD design and CAD drawing output, outer scaffold structure stress analysis is automatically completed on the basis of outer scaffold modeling, automatic drawing output after three-dimensional model and formwork optimization design is generated, and huge and heavy work caused by traditional design change is solved in a one-key mode.