The utility model provides a power supply line adjusting device that relaxes, which comprises a sleeve, telescopic screw rod, electric wire chuck device and control terminal, the sleeve sets up the motor, be equipped with first shaft hole and second shaft hole in the sleeve, downthehole fixed axle and the antifriction bearing of setting up of the primary shaft, the fixed axle passes through go -between and insulating pillar fixed connection, the secondary shaft the downthehole outer thread to match who is equipped with internal thread and telescopic screw rod close, slide damper is connected to telescopic screw rod's one end, slide damper establishes at the primary shaft downtheholely, telescopic screw rod's other end connecting wire chuck device, electric wire chuck device includes dead lever and clamping device, set up temperature sensor on the insulating pillar, temperature sensor and motor connection control terminal, control terminal sets up subaerial. The utility model discloses structurally adopt simple screw -thread fit's mode, structural simple reasonable, the staff can accomplish the take -up of electric wire or lax according to the change of temperature subaerial, and operation safe and reliable, the working property is stable, convenient adjusts.