The invention provides an expressing method for bending component drawing based on physical reference and is suitable for the construction technology of building steel structure. The expressing method comprises that a, according to the actual situation, the object which is good for installation is selected as the reference to express the bending component, and the reference is taken as the datum in the drawings; b, the reference is expressed in the drawings; c, the size between the reference and the to-express bending component is calculated; d, the bending component in the drawing is expressed; e, the size of the reference and the to-express bending component are labeled to complete the expression of the whole drawing. The expressing method for bending component drawing based on physical reference enables the drawing to be simple and clear and is convenient for the constructors to identify the drawing. The expressing method for bending component drawing based on physical reference is helpful for the on-site constructors to understand the location of the installation structure in the field and reduces an error in the installation process, and is favorable for field installation.