A connector assembly includes a plug connector and a receptacle connector mateable with each other. The plug connector includes a plug insulative housing and a pair of plug power contacts. The plug insulative housing includes a first plug cavity, a first plate cantileveredly extending into the first plug cavity, and upper and lower plug contact slots in communication with the first plug cavity. The pair of plug power contacts are respectively received in the upper and lower plug contact slots. Each plug power contact includes a flat contacting section exposed to the first plug cavity and a first soldering section. The flat contacting sections are positioned on upper and lower surfaces of the first plate, respectively. The plug connector and the receptacle connector define heat dissipation channels in communication with each other in order that generating heat can be effectively dissipated to the air.