A low impurity magnesium alloy has bean prepared. Deformation behavior in cold-rolling and corrosion behavior of the alloy were compared with those of a commercial alloy. The specimens were cold-rolled at room temperature with reduction rates of 0~80 %. Transmission electron microscopic observations on the cold-rolled specimens were carried out. In the case of the low impurity magnesium alloy, recrystallization easily occurred. Analyses of microstructures in the deformed specimens were carried out by means of EBSP, and the recrystallization phenomena have been discussed. Another effect of lowering the impurities is to improve a corrosion resistance with changing the corrosion morphology.