The invention provides a vertical tension-free movable sleeve, which solves the problems of large power consumption of a storage mechanism, serious energy waste, high production cost, low plate shape protection capacity, application limitation to occasion when surface protection requirements are low, and low safety of the production line in the prior art. The invention adopts a new technical scheme that the vertical tension-free movable sleeve comprises a machine frame (2), a guardrail (3), pinch rolls (4), an upper position detection device (6), an isolating device (7) and a lower position detection device (8), wherein the pinch rolls (4) are positioned on the top of the machine frame (2); the isolating device (7) is arranged between the top and bottom of the machine frame; and the position detection devices for detecting the position of a steel strip are arranged on cross beams (13) arranged on the top and bottom of the machine frame. When the technique is adopted, power consumption is small, energy is saved, the storage capacity is high, the plate shape protection performance is high, damage to the steel strips is avoided, and the safety is high.