Stair lift is transportation technology with electrical mechanical equipment to assist vertical movements in buildings, and it is used specifically and individually by the elderly and people with disabilities . This paper has two objectives. The first is to optimize the ability of the existing stair lift structure by developing lighter stair lift designs and materials without reducing the capability of the stair lift. The second is to design a braking system on the stair lift. The optimization of a stair lift structural design is needed to ensure that the strength of the stair lift structure complies with the requirements of ASME standard 18.1. The methodologies of this study are redesigning and conducting numerical simulations with the finite element to get the optimum result. Numerical simulations on the guide rails were carried out on A36 steel and 6063 T5 aluminum materials by comparing 30o and 45o stair lift inclinations. The maximum load is 270.4 kg. The distance of support is 1000 mm. From the simulation results, the 6063 T5 aluminum profile can be used as a material substitution for guide rails. The chains for driving links need to be strengthened by adding the dimensions of the chain or increasing the number of chains. The maximum temperature distribution on the disc brakes is 130.56 °C.