The invention discloses an elastic yarn, and belongs to the technical field of textile engineering. The yarn comprises a group of elastic core fibers, a group of polyester staple fibers and a group ofstaple fibers coating on the outermost layer, the elastic core fibers and the polyester staple fibers are drafted and are output by a front roller with the staple fibers used for coating, twisting and winding are carried out to form the yarn with the polyester staple fibers and the elastic core fibers inside and other staple fibers outside. According to the invention, the polyester staple fiber roving is drafted and twisted with another staple fiber roving, and meanwhile, the elastic core fibers are fed, so that the elastic yarn which has the advantages of easy dyeing, excellent elasticity, abrasion resistance, pilling resistance, water washing resistance and water retention property is produced; the elastic yarn is used as a weft yarn, the warp yarn is not limited, the elastic recovery rate of a woven fabric is high, the elastic recovery rate of the weft is between 55-85%, the abrasion and pilling grade of the woven fabric is 3.5-5, and the wrinkle recovery performance grade is 4-5.