Semi-solid aluminumAluminum slurry exhibits an unpredictable rheology and filling dynamics, which is determined by cast microstructureMicrostructure and influenced by castingCasting parameters, such as solid fraction and shear rate/time. In this respect, understanding the rheological behavior is crucial for semi-solid castingCasting to obtain excellent filling behavior and improve mechanical propertiesMechanical properties. The rheology of AlMg5Si2Mn alloy was studied by rotational rheometry at various solid fractions and shear rates to reveal the thixotropy of the semi-solid region. Three different types of rheological experiments are performed to correlate slurry morphology with its flow behavior: continuous cooling test, shear jump test, and shear time test. This study can provide a solution for semi-solid castingCasting process by characterizing the forming behavior of Magsimal-59 with corresponding rheologicalRheocasting properties.