Based on the long-term clinical practice experience and the national 973 program on “Research for TCM etiology and pathogenesis of HIV/AIDS”， we put forward and verified the theory of the pathogenesis of AIDS shall be “Ai virus hurting the promordial Qi”. The theory pointed out that the pathogen was the virus， and the basic pathogenesis was promordial Qi being hurt. And dampness played a key role all the time. Due to the TCM theory of “Like attracts like”， HIV was more prone to attack human whose body constitution were dampness.