A light-and-shadow decoration includes a main decorative object, an omnidirectional rotation mechanism, and an electrical control unit. The main decorative object includes a three-dimensional structure and has one side that is provided with a retaining seat. The omnidirectional rotation mechanism includes a support axle, a rotation base, and a projector. The support axle has two ends each provided with a universal-joint ball. The rotation base and the projector are respectively connected to the two ends of the support axle. The projector has one side on which a lighting cover is mounted. The electrical control unit includes a power supply portion and at least one light-emitting element. Light from the light-emitting element transmits through the lighting cover to project to the outside. As such, the omnidirectional rotation mechanism enables rotation of the light source relative to the main decorative object and the support axle for adjusting a projection direction thereof.