The military uniform is worn to defend against enemy. Its function has an important effect on its changing. As once the means of combat was the collective formation, soldiers fought with swords and bows, or on horses. After the invention of gun powder, however, it became changed to the scattering formation. Therefore, it became impossible to fight on great armors any more. the armors and helmets made of iron, used light, materials, became those of Doosuingab (豆錫鱗甲), Soejagab(鎖子甲), Pigab(皮甲), Jigab(紙甲). The Doojunggab(頭釘甲) which presented a grand appearance came into existence. At last the Chullic and GooGoonbok made of clothing were worn. Korean military uniform were influenced by Chines military uniform. Korean armors had an influence on Japanese. As follows, I will study on Chinese and Korean armors with the changes of the times.