The invention discloses coated sand for selective laser sintering and a preparation method thereof. The coated sand comprises crude sand, a compound binder, a curing agent, a lubricating agent and a light absorber, wherein the compound binder comprises phenolic resin and epoxy resin; the curing agent is formamine; the lubricating agent is zinc stearate, calcium stearate or lithium stearate; and the light absorber is carbon black. The preparation method comprises the following steps: firstly, carrying out freeze grinding on the epoxy resin; then selecting epoxy resin powder with suitable particle size distribution by a sieving method; and finally, evenly mixing a certain ratio of epoxy resin powder, the carbon black and phenolic resin coated sand prepared by the existing process. Due to the fact that the strength of the SLS formed part of the coated sand is higher, the coated sand can be used for SLS of casting sand moulds (cores) with large-size and complicated structures.