Injection moulding is one of the most important manufacturing processes for mass production of complex plastic parts. The quality of injection moulded parts depends not only on the material, shape, and function of the part design, but also on how the material is processed during moulding. Traditional design approaches based on intuition, prior experience, and trial-and-error methodology have been becoming less efficient and effective. With advances in numerical modelling and computer simulation techniques, there have been tremendous efforts made to develop computer simulation tools to facilitate injection moulding design and process set-up. This paper reviews the history of research and development in the filling simulation of injection moulding. The existing models are classified into three categories: one-dimensional models, 2.5D models, and three-dimensional models. The basic features and relative key techniques about these models have been discussed. The techniques of tacking the moving flow front have also been presented. It is then followed by conclusions and discussions of these mentioned models.