Provided is a sand setting circulating device for wave-current tank test tailings. A sand collection device is arranged at a front end of a tail gate of a tank body for performing primary collection on a bed-load sand body with a large particle size; a sand-water separating device is arranged at a tail end of the tank body for performing sand-water separation on tail water subjected to energy dissipation so as to perform secondary collection on a suspended load sand body with a small particle size, the sand-water separating device comprising a collection barrel and a sand suction device mounted in the collection barrel; a water outlet is formed in an upper part of the collection barrel, and separated clear water flows into a clear water reservoir through a water return pipe for cyclic utilization; and a computer is arranged for intelligent control.