The invention discloses high-strength flame-retardant protection yarn which comprises a yarn body. The yarn body is provided with a long filament reinforcing layer, a fiber thermal insulating layer and a fiber protecting layer from inside to outside in sequence. Through the high-efficiency flame-retardant performance of the fiber protecting layer, the flame-retardant effect is greatly improved; through the excellent thermal insulating performance of the fiber thermal insulating layer, the yarn has an outstanding protecting effect; through the high-strength performance of the long filament reinforcing layer, the brute force of the yarn is remarkably improved. In addition, the fiber protecting layer has good moisture absorption performance, and the good wearing comfort level of a fabric woven from the yarn is ensured; the yarn is easy to dye, and the colors of the yarn, the fabric and clothes are enriched; the fiber protecting layer has good radiation resistant performance, and the radiation resistance performance of the yarn is stable.