During producing bimetallic aluminum alloys by centrifugal casting, the presence of aluminium oxide film on the solid surface prevents the achievement of suitable metallurgical bond between two layers . In this study aims to investigate the effect of the second-layer casting conditions were investigated on the properties of the bimetallic joint between the strontium-modified aluminum alloy A356 (first layer) and the Al-15Sn-4Si-1Mg alloy (second layer) using the centrifugal casting method. The temperature of the inner surface of the first layer (566, 530, and 500 °C) and the ratio of the second-layer thickness to the first-layer thickness (0.1, 0.2, and 0.3) were selected as process variables. The microstructure and strength properties of produced samples were evaluated to characterize the interface between the two layers. Microstructural observations showed that due to the presence of magnesium and tin elements in the second layer alloy along with centrifugal force, the aluminium oxide layer on the solid surface of A356 was subjected to reduction and rupture. Based on the results of the joint shear strength test, the sample cast at the first layer inner surface temperature of 530 °C and the ratio of 0.2 showed the highest shear strength of 99.40 MPa, and the sample with the first layer inner surface temperature of 500 °C and the ratio of 0.1 showed the lowest shear strength of 41.48 MPa at the joint.