Abstract:  Emotional tears, stimulated tears and basic tears have with their own origin, mechanism, function and excluded paths. We focus on the controversial points in basic tear secretion mechanism, and according to our clinical observation results we put forward the hypothesis that "periodic blink is the power source of secrete basal tear”. We describe in this paper that the periodic blink movement starting basal tear secretion of tear function mechanism and operation. The eyelid movement promotes two tear rivers become one again divides into two, which periodically updates the front tear film, and at the same time blink movement squeezing and relaxing extrusion lacrimal sac, pulling the canalicular wall produces lacrimal pump action. The front tear film is evaporated out and at the same time drives the tear rivers and orderly migrating to the tear lake, which is the lacrimal non-tube section part. Lacrimal pump acts to take tears from the tears lake into the lacrimal duct to exclude. There is mucous membrane between the junction of lacrimal sac, lacrimal canaliculus and nasolacrimal duct. The directional swing of the nasolacrimal duct cilium makes basic tear transitional to the nasolacrimal duct outlet, and tear degasification enters the respiratory airflow, discharge or inhalation. This article explains the necessity of lacrimal system including the conjunctiva, eyelids and conjunctival sac, eyelid blinking. We firstly propose some new concepts, such as the ordinary tear, vaporization of lacrimal duct and lacrimal non-tube section part, tube section part and the connection point of the two section parts. (Ophthalmol CHN, 2014, 23: 226-229)