The invention relates to a packaging mechanism of injection. The packaging mechanism of the injection is formed by erectly arranging a base plate on a base, forming an operation space in one side of the base plate and then arranging a conveying channel at the bottom of the base plate, wherein an output part on one side of the conveying channel extends to one side edge of the base; a feeding part is arranged on the other side of the conveying channel; a control machine plate and a plurality of motors of a drive unit are assembled on the other side, opposite to the operation space, of the base plate; the plurality of the motors are connected with power transmission parts correspondingly; the power transmission parts are correspondingly connected with a plurality of drive shafts which extend to the operation space; and an injection feeding part, two packaging bag feeding parts on the two sides, a sealing part, a bag body detector, a trimming part and a sensor of a packaging unit are assembled on each drive shaft in the operation space; the two packaging bag feeding parts are arranged on the two sides of each drive shaft correspondingly; furthermore, the bottoms of the trimming parts are positioned above the feeding part of the conveying channel, so that the aim of automatically packaging the injection is fulfilled.