One of the most complicated subjects of the injection molding is the flow analysis. The flow of the plastic depends on the structure of the plastic material and the geometry of the mold cavity and the injection process parameters. The flow analysis and the simulations are achieved according to the numerical solution of the non linear differential governing equations. In this study, the Navier-Stokes equations are solved using the Finite Control Volume Method. The staggered grid system is used for the Full Implicit discretization method and SIMPLE algorithm is preferred for the calculation of the pressure. The Boussinesq approach is applicated to determine the density variations and the Power Law viscosity model is choosen. The melt flow is analyzed by Phoenics code. Both numerical analysis and the experiments have been realized for the same processing conditions and the same plastic material. HDPE is studied as a plastic material. It is shown that the theoretical and the experimental results are in good agreement.