The invention relates to a torque sensor for an electrically-assisted vehicle, which comprises a driving part for introducing power, a torque output part arranged on an outer lane of the driving part, a driven part driven by the driving part through a connecting part, and a displacement sensor arranged in an inner lane of the driven part, wherein a moving clearance is reserved between the driven part and the driving part; an elastic part is arranged between the driven part and the driving part; the circumference of the torque output part is provided with a radial plug jack; the outer circumference of the driven part is provided with a guide spiral groove; a cross shaft is inserted in the plug jack and the guide spiral groove; and one section of the cross shaft is connected with the guide spiral groove through a bearing, while the other section of the cross shaft is arranged in the radial plug jack. The torque output part is provided with the plug jack, meanwhile, the bearing is arranged between the cross shaft and the guide spiral groove, so as to reduce the friction between the cross shaft and the guide spiral groove, thereby greatly reducing the axial motion-resistance force, making the radial motion effectively transform to axial displacement, improving detection accuracy and reducing abrasion.