Magnesium alloys are expected as the lightest structural metal in many industrial fields. Recently, many atempt to use wrought magnesium alloys for automobiles and electronic devices have been performed. Electronic devices such as personal computers and mini-music players have been made by magnesium rolled sheets and extruded sheets.Extruded sheets are very effective for cost savings, because we can obtain thin plates at I process.These products are made by deep drawing or forging at elevated temperature.To enlarge usage of wrought magnesium alloys, it is very important to improve plastic formavility at low temperature.Manganese is a very important alloy element because it improves corrosion resisitanse and it is effective for grain refainning But at plastic deformation, large Al-Mn compounds sometimes prevent formability. In this study, we prepared AZ31system. alloys and AZ10 system alloys which have 0 to 0.8%manganese, and we investigated influence of manganese on extrusion loads, surface cracks, internal structure, and mechanical properties. AZ10 is the alloy which we have proposed that it has high extrusion productivity.