The invention relates to a production apparatus for producing high-grade fused magnesite from tailings, comprising a ball press, a light calcining kiln, a rolling machine, a screening machine, a mixing machine, a high-strength ball press, and a fused magnesite electric arc furnace; a furnace-back treatment device is arranged at an outlet of the fused magnesite electric arc furnace and includes a conveyer belt, a spraying device, a washing device and a precipitating device, the spraying device is arranged above the conveyer belt, the washing device is arranged at a discharge port of the conveyer belt, and the precipitating device is connected with the washing device through a water pipe. The production apparatus produces high-grade fused magnesite from magnesite tailings, the yield and high-quality product rate of the high-grade fused magnesite are increased, and the yield of fused magnesia with MgO content of 97.5% and above may reach 70% and above. Low-grade magnesite resources are effectively utilized, and the objective of environment protection and energy conservation is achieved.