In this article the effect of hot rolling process on properties and microstructure of Al-B4C composite is investigated. To produce the composite samples, 3 vol.% B4C particles with 300 nm average grain size added to melted Al-356 alloy. Rolling process was done at 350 °C on vortex samples that is made after 15 minutes mixing at 850 °C. Porosimetry, hardness and tensile strength tests were carried out to investigate the physical and mechanical properties of composite samples. Microstructures of the samples were also investigated by using scanning electron microscopy. The results indicate lowering the amount of porosity, increasing hardness and increasing tensile strength of rolling composites. The amount of porosity before rolling process was 2.05% that is decreased to 0.35% after rolling process. Tensile strength and hardness of composites before and after rolling process achieved 178 MPa and 293 MPa and 62 HBN and 101 HBN respectively. Also hot rolling process caused to more ductile fracture of composites that is produced by vortex. Tensile strength and hardness of composites before and after rolling process achieved 178 MPa and 293 MPa and 62 HBN and 101 HBN respectively. Also hot rolling process caused to more ductile fracture of composites that is produced by vortex.