The present invention relates to a stator winder automatic wire thread tension device. The device comprises an installation plate, a wire wheel, an installation rack for installation of the wire wheel and a tension device located at the upstream of the wire wheel; the installation rack comprises a vertical connecting rod and an inverted U-shaped fork head located at the lower end of the connecting rod; the installation plate is provided with a hollow sleeve; the upper end of the connecting rod stretches into the sleeve, and is connected with the installation plate through a spring; the lower end of the sleeve is provided with two vertical poles; the device also comprises a silicone tube matching with the wiring trough of the wire wheel; two ends of the silicone tube are respectively connected with the lower ends of the poles; and when wiring is normally performed, the wire wheel goes downwards by the outgoing line tensile force of the tension device and the copper wire, the installation rack goes downwards under the action of the guidance of the sleeve, the spring is stretched, when the wiring is stopped, the copper wire outgoing line tensile force disappears, the tension device goes on line outgoing, the spring recovers the deformation to drive the wire wheel to go upwards, and the silicone tube at the lower ends of the poles are matched with the wiring trough of the wire wheel for wire clamping. The clamping and relieving of the copper wire do not need to perform manual control and programming control, and the automation degree is high.