The invention relates to an automatic kinking device for a bacterium stick packaging machine. The automatic kinking device comprises a rack. A feeding mechanism is arranged on the rack. The feeding mechanism is connected to a conveying mechanism used for conveying bacterium sticks. The conveying mechanism is connected to a kinking mechanism used for sealing a bacterium stick bag opening. The kinking mechanism comprises a clamping jaw arranged above the bacterium stick bag opening. The clamping jaw is mainly composed of a plurality of clamping heads which can be started and closed to clamp the bacterium stick bag opening, and a first air cylinder which is used for driving the closed clamping heads to move downwards to compact a bacterium stick. Or, the kinking mechanism comprises a bending assembly which is arranged above the bacterium stick bag opening and is capable of being started and closed to bend the bacterium stick bag opening. The bending assembly is mainly composed of a bar-shaped body and a leftwards-opened C-shaped body. The kinking mechanism further comprises a kinking female die and a kink sending punch which are arranged on the two sides of the bacterium stick bag opening. The invention further relates to a kinking method of the automatic kinking device of the bacterium stick packaging machine. The automatic kinking device for the bacterium stick packaging machine and the kinking method are reasonable in structural design, simple in technology method, high in bacterium stick kinking efficiency and high in automation degree.