Abstract: Vascular bundles of the pedicel in flower of Commelina communis were scattered within central fundamental tissues.The vascular system changed complexly from the top of the pedicel to the base of the locule.The six bundles inclined to outerside of them bore the inner-outer or left-right branches,of which three outer branches of those only borne inner-outer branches entered the sepal to become its vascular system,three inner branches of those entered three stamen of outer whorl, of which the other three bundles firstly divided into two respectively,then the outer one divided into 3～5 strands which all entered the petal,the inner one no longer divided and extended into the stamen of inner whorl.The other six bundles,which were nearly round,continuously expanded towards the top,of which three bundles entered the ovary wall after extended into the locule region to become the carpellary dorsal bundles which finally entered the style,of which the other three moved to center to become the placenta vascular bundles which were absent at the top of the locule.The origin and evolution of the vascular system of the flower in Commelina communis and the taxa concerned were discussed in this paper.