The invention discloses a tentering setting machine with a flue cooling device. The tentering setting machine comprises a drying setting box body, vertical branch pipes, a main flue, a condensation pipeline and a smoke exhaust flue; the main flue communicates with the drying setting box body through the multiple vertical branch pipes and is located above the drying setting box body; the smoke exhaust flue is located on the upper portion of the main flue and vertically fixed to one side of the main flue, and the main flue communicates with the smoke exhaust flue; and the condensation pipeline is wound around the outer wall of the main flue. The tentering setting machine is simple in structure, convenient to install, low in cost and capable of effectively cooling the main flue and lowering the temperature of the main flue, and fires caused by the smoke exhaust flue are avoided.