Injection molding is one of the most important polymer processing operations. The results from numerical simulation of this process provide valuable information in designing part/ mold or choosing process parameters. The flow simulation is based on a hybrid finite-element/ finite-difference numerical solution of the generalized Hele-Shaw flow of a non - Newtonian fluid under non - isothermal condition. A unified expression in terms of flow rate is set up for both entrance and interior nodes. In advancing the melt front

the commonly used method of determining time step is modified. Two examples are given to show the validity of the numerical method.