In this study, the influence of MgO addition on mechanical properties of the injection molded alumina was investigated. Firstly, alumina feedstocks (without adding MgO) were prepared to determine the optimum powder/binder ratio by the capillary rheometer. Then, MgO was added at 0.5, 1 and 1.5 wt.% to alumina feedstocks at the optimum ratio. Moldflow simulation analysis (MSA) was performed to obtain injection parameters (injection pressure, flow rate and feedstock temperature) before the real molding operation. Through the agency of the pre-operating parameters obtained from MSA, preliminary trials were carried out by molding machine for successful specimens (tensile and bending). By comparison of experimental and analytical results, the error rate of injection parameters was determined for both specimens. The maximum strengths of bending and tensile test values were found 158 MPa and 69 MPa (in specimens containing 1 wt.% MgO), respectively. Analysis of SEM revealed that specimens containing 1 wt.% MgO had less porosity.