Abstract: Physics-based human motion simulation is a cross research field in robotics, biomechanics and computer science, whose research goal is to build a computable model for human movement such that the natural human motion satisfying the given constraints could be simulated in the virtual environment. Compared with the traditional human animation, the simulated human motion must obey the Newtons law of motion. And therefore physics-based human motion simulation can be used for not only the special effects generation but also the education and training of physical tasks. Firstly, the origin of human motion simulation and some typical applications are introduced. Secondly, the key technologies of human motion simulation are elaborated. In this part, the simplified geometry model and physics model of human used in human motion simulation is introduced. And then the current methods are classified into two types: the forward dynamics based human motion simulation and the inverse dynamics based human motion simulation. The development history and recent research of these two methods are introduced in detail. Finally, based on the simulation of interactive action between human and objects, the verification of the result of simulation and so on, some future directions in human motion simulation are discussed.