A paper discharge mechanism, and a printer and a terminal device having the paper discharge mechanism. The paper discharge mechanism includes a frame, a rotary plate, and a paper tear bar. The rotary plate is provided at one side of a conveying passage of printing paper, one end thereof connected to the frame through a pivot shaft and the other end unsupported, and is forced to rotate along a first direction around the pivot shaft when the printing paper is pulled by an external force. The paper tear bar is fixedly provided in the rotation path of the rotary plate. Wherein, the rotary plate is provided with a gap. When the rotary plate rotates along the first direction, the paper tear bar extends out of the gap and contacts the printing paper to tear the printing paper.