Wang Yang-Ming has experienced frustrations frequently for seeking knowledge at youth and sufferings from actual life at middle age, then perceives intuitively the main point of Dashiue's phrase ”to investigate things and to extend knowledge to the utmost”, and founds his academic theory of unity in essence and action by unity of knowing and doing. The military achievements he made repeatedly afterward have also proved that his moral culture tallies with the idea of Internal Holy and External King of Confucius' school. This article intend to probe into related elements between his military achievements and moral culture. Firstly, we represent his three minitary achievements in chronological order, then get into finding out what relationship between his achievements and moral culture, the prime essentials among them should be his scholastic attainment of serene mind and discipline of actual affairs. Finally, we should inspect corrupt practices spreaded out by disciples of Yang-Ming School after inheriting his practical philosophy, that can awake us to avoid the hidden forked roads along with Yang-Ming's academic theory.