A biomechanical musculo-skeletal model of upper limb is presented in this paper, which can provide accurate representations of muscles and joints, and capture important interactions between joints. The upper limb model is made up of seven segments: ribs, sternum, clavicle, scapular, humerus, radius and ulna, considered as a single rigid body respectively and includes 22 muscles. The individual muscle forces can be calculated by using an electromyography (EMG) assisted method, which is verified by comparing the simulation results with other researches of an elbow flexion motion. These comparisons show that the muscle forces and the estimated joint moment match well with previous literatures. © 2011 Shanghai Jiaotong University and Springer-Verlag Berlin Heidelberg.