One of the highest components of disability is difficulty in walking, which is caused by disorders of the lower limbs due to disease and joint injuries that occur in athletes. Ankle Foot Orthosis is a tool used to overcome this limitation. Therefore, designing the orthosis with biomechanical aspects and user comfort is very important. This research has been done by examining the effects of changes in structural mass on articulated and non-articulated AFO types, and this simulation is used to determine the dynamic response that occurred. ANSYS Workbench software was used in the simulation, and a dynamic load of a walking human with a gait cycle was used. Finally, the AFO prototype uses the 3D printing method based on the optimum design for user convenience. The results showed that Articulate AFO has higher stresses and deformations than non-articulated. Still, for each system, the stresses tend to decrease from 2 to 5 mm thick, but paying attention to heavy aspects is necessary. The final design for non-articulated is 3 mm, while for Articulated, it is 4 mm.