The invention provides a packaging mechanism. The packaging mechanism comprises a first installation frame, a driving device, a grabbing device and a placing module, wherein the first installation frame is provided with a rail frame; the driving device is slidably arranged on the rail frame; the grabbing device is fixedly connected to the driving device; the placing module is arranged at the lower end of the grabbing device and corresponds to the grabbing device. The grabbing device further comprises an auxiliary flatness guiding module. The packaging mechanism has the beneficial effects that the grabbing device is arranged and used for grabbing a spare part bag; the grabbing device is used in cooperation with a vacuum generator, a vacuum filter and a sucker to complete grabbing of the spare part bag; the auxiliary flatness guiding module arranged on the grabbing device is used in cooperation with an auxiliary flatness guiding driving piece and an auxiliary flatness guiding insertion plate for complete flatness guiding of the spare part bag packaged into a packaging box.