The invention provides a stretched flexible ankle wearable power-assisted device driven by twisted pair, which includes a foot support plate, a flexible joint made of soft materials and rigid components, an ankle wearable component connected with the flexible joint, and a driving ankle joint. The twisted wire driving part of the movement, the flexible joint is composed of a limit rod fully encapsulated in the soft material and a rigid connector partially encapsulated in the soft material, while the twisted wire driving part is composed of a motor, a gear transmission system, and a twisted pair. The ankle joint power-assisted mechanism drives two thin wires to twist each other through the motor, and twists them into a double helix structure in advance. Through the degree of tightness of the twist, it can realize stretching and relaxation similar to muscles, and then assist the wearer to walk. The special flexible joint can realize free movement in the directions of dorsiflexion, plantarflexion and internal rotation and external rotation. A motor drives the twisted-pair structure on both sides to achieve bilateral stretching and relaxation functions at the same time, and can provide safety for the ankle joint. Protective function.