Aluminum and its alloys are used in a wide range of industrial applications from low density, high strength and a variety of structural materials. In this study, the effects of Ca addition on the microstructure and mechanical properties of Al-1wt.%RE alloys were investigated. The melt was held at 800 °C for 20 minutes and poured into a mold. The cast Al alloy was hot extruded with a rod having a diameter of 12 mm and a reduction ratio of 38:1. Al-1wt.%RE alloy consists of Al, Al11RE₃ phase. The Al₂Ca phase is increased by increasing the Ca content to 0.2 to 0.4 wt.%. As the Ca content increased from 0 to 0.4 wt.%, the average grain size of the extruded Al alloy decreased by 739.8, 400.8 and 155.0 μm. The tensile strengths were increased to 74.25, 76.53, and 79.52 MPa. The electrical conductivity of Al-RE alloy with Ca addition decreased to 60.32, 58.15 and 57.89% IACS.