Through investigation into the change of LI Jian-cheng and LI Shi-min' status in the military and political pattern in the early Tang Dynasty, it is found that LI Jian-cheng was always higher than LI Shi-min in status and his responsibility was always heavier than that of LI Shi-min when LI Yuan was the emperor; LI Jian-cheng was an excellent emperor heir with the world pattern in his heart and he had got great support from LI Yuan; when LI Shi-min gained power after the Xuanwumen coup, he had to properly placate the forces operated by LI Jian-cheng for many years, at the same time, continue the implementation of national fundamental policy following confrontation Turkic strategy made by his father and his brother; LI Jian-cheng's excellence forced LI Shi-min to actively try to catch up so as to convince the public; to some extent, LI Shi-min's greatness is promoted by his same great brother.