In this study, the effect of lanthanum (La) on microstructure and corrosion properties of hot-rolled AZ31 Mg alloys was investigated. Light optical microscopy, scanning electron microscopy, and X-ray diffraction were applied for microstructure analysis. Potentiodynamic corrosion and immersion tests were being tried to assess the La effect on corrosion behavior. Moreover, how the rolling parameters and surface smoothness were changed of the corrosion rate was evaluated. Corrosion performance was developed by adding La and the corrosion rate was changed with the rolling speed.