Objective To design an overall unloading knee brace, and analyze the relationship between the unloading force and the position of the brace as well as the thigh bracket-thigh pressure. Methods Based on biomechanical experimental platform, the mechanical and kinematic analysis on squatting down-standing upright motion was conducted to evaluate unloading capacity of the overall unloading knee brace. Results The unloading forces supplied by the brace ranged from 0 to 200 N. The forces were larger with the brace hinges installed on the front-top of the knee, and the unloading forces increased with the pressure between the thigh and thigh bracket increasing. Conclusions The proposed overall unloading knee brace can partly reduce knee force, and its unloading forces are related to the installation site of the brace as well as the elasticity of the belts.