Abstract: A design method of an assistive device and an electronic system of assistive device design are provided. The design method of the assistive device are adapted for an electronic devices including a processor. The design method includes: obtaining a point cloud data of a limb part; determining a plurality of reference cross sections according to the point cloud data, wherein each of the reference cross sections is determined corresponding to bone protrusion feature points of the point cloud data, wherein the bone protrusion feature points are corresponding to the bony prominences of the limb parts respectively; establishing an initial digital model of the assistive device according to the reference cross sections; and performing a structural simulation analysis according to the initial digital model and design limitations to obtain a product digital model of the assistive device.