The invention relates to fire-retardant fiber blended yarn, a preparation method of the fire-retardant fiber blended yarn and fabrics of the fire-retardant fiber blended yarn. Double-layer fibers are used in the fire-retardant fiber blended yarn which comprises a surface layer and a core layer, the surface layer is composed of, by weight percentage, 20-30% of phenolic fibers, 20-25% of fire-retardant acrylic fibers, 30-40% of copolyamide fibers, 20-30% of antistatic synthetic fibers in a blending mode, the characteristics of the fibers can be sufficiently utilized, the problem existing in single fibers is solved, the spinnability of the fibers is improved, and a fire-retardant effect is improved. The core layer is composed of, by weight percentage, 10-20% of wool fibers, 30-40% of nylon fibers and 40-50% of polyester fibers, cost is lowered, and the air permeability of the fibers is improved. Fire retardant soaking treatment is conducted on the fibers of the core layer, and the core layer is made to have the fire-retardant capacity. The fire-retardant fiber blended yarn can be applied to clothing, home textiles, sports products, health care products, and fire-proof fabrics.