By analyzing the core elements of menstrual physiology and the fundamental mechanism of menstruation， the theory of “menstrual physiology” in traditional Chinese medicine （TCM） has been initially constructed. In this theory， kidney

qi

，

tiangui

（天癸）， uterus with appendages， and

chong

（冲），

ren

（任） and

du mai

（督脉） are taken as the basic elements， and the “

tiangui

-uterus with appendages” in the unity of heaven and earth is constructed as the container that harbors life， which is characterized by ascending， descending， exiting and entering. The menstrual basis on the junction of heaven and earth， as well as the rule densed with the donation of rain and dew are explained. It is proposed that the kidney

qi

is the motive force of menstrual physiology， and its function of protecting the

zang

（脏） of uterus with appendages is the key， based on which the

qi

transformation theory of menstrual physiology is preliminarily formulated. Simultaneously， by taking

tiangui

，

zang fu

（脏腑） and

chong， ren

as the entry points， the main issues of menstrual physiology theory are initially clarified， so as to further promote the clinical application of this theory.