A swing comprises a support, a balance wheel, a swing plate, a magnetohydrodynamic device and a controller. The balance wheel is provided with a central shaft, a swing eccentric shaft and a swinging eccentric shaft, the swing eccentric shaft and the swinging eccentric shaft are arranged at different positions of the balance wheel, and the central shaft of the balance wheel is connected with a bearing block of the support in a movable fit manner; the magnetohydrodynamic device comprises a cylinder, a piston, a piston rod, magnetic fluid and an electromagnetic coil, the piston and the magnetic fluid are arranged in a cavity of the cylinder, the cylinder is hinged to the support, and the piston rod is hinged to the swinging eccentric shaft. The swing has the advantages that the piston and the piston rod ascend and descend in the magnetic fluid according to rhythm of music for children under the control of the controller, the piston rod drives the balance wheel to swing along with the rhythm of the music for the children, and the balance wheel and the swing eccentric shaft drive the swing plate to swing according to the rhythm of the music for the children, so that the children, particularly babies, on the swing can swing along with the music for the children, and the swing playing interestingness is improved.