The rank of imperial consorts system in Tang Dynasty, under the Empress, there were four concubines which were Guifei, Shufei, Defei and Xianfei. Basically, the rank of imperial consorts system didn't have big change before the end of Tang Dynasty. During Emperor Gaozong's reign, he had created a title "Chenfei" for Wu Zetian. The position of Chenfei was above the four concubines . However, the title of Chenfei were opposed by Ministers. Therefore, Wu Zetian was the only one had the title of Chenfei in Tang Dynasty. Moreover, the position of four concubines didn't change because of Chenfei. In the early reign of Emperor Xuanzong, the rank of imperial consorts remained the system of one Empress and four princesses. Afterwards, due to Empor Xuanzong doted on Wu Huifei, he changed the one empress and four concubines system to one empress and three concubines. Also, the titles were changed to be totally different than before. However, finally the system still returned to the original one as one empress and four concubines. The purpose of this paper is research on the course of Empor Xuanzong changed of the rank of imperial consorts during Kaiyuan Era and the related stories of three concubines - Wu Huifei, Zhao Lifei, and Liu Huafei.