An exemplary magnesium alloy includes: by weight, magnesium as a main ingredient, aluminum in an amount from 7.5% to 7.8%, zinc in an amount from 0.35% to 1.0%, manganese in an amount from 0.15% to 0.5%, silicon less than 0.1%, copper less than 0.03%, iron less than 0.005%, and nickel less than 0.002%. The present invention also provides a thin workpiece made of the magnesium alloy.