Research and development of magnesium alloys depends largely on the metallurgist's understanding and ability to control the microstructure of the as-cast part. This work comprises the determination of experimental input parameters to run a successful and vast informative simulation using state of the art software. Various thermodynamic analyses have been used to study the thermo physical properties of binary magnesium-aluminum alloys, and the resultant microstructures have been simulated and then compared with the experimental output. The calculated heat distributions have been used to simulate the resulting microstructure using the phase-field method. This paper presents an overview of a range of ideas that have been undertaken to improve our understanding on the gravity diecasting behavior & solidification characteristics of Mg-Al alloys. It follows the solidification process of binary alloys Mg-Al, beginning with the nucleation and grain refinement. The simulated and the experimental results are compared and used for validation.