The invention provides a rotary mechanical sand barrier, which includes a plurality of sand resistant plates with air holes in the plate surfaces, wherein the bottom surface of each sand resistant plate is fixedly connected with a vertical rotating shaft; and one rotating shaft is connected with a mounting base and can rotate in a reciprocating way around the self axis. During the actual use, the two neighboring sand resistant plates are connected through a synchronizing mechanism, one of the sand resistant plates is mounted with an anemoscope and an adjustment drive device, and the adjustment drive device drives the sand resistant plate to rotate. The sand resistant plates can rotate according to the wind direction, so as to enable the sand resistant plates to be permanently vertical to the harmful wind direction, as a result the maximum sand resisting efficiency is brought into full play, the on-site construction is quick and convenient, the main components can be repeatedly used, the construction difficulty is less, the cost is low, and the rotary mechanical sand barrier can quickly and effectively prevent and treat the blown-sand disaster endangering the protecting objects as railways, roads and ancient sites.