With the increasing attention to fire safety and environmental protection awareness, flame-retardant rayon fibers(viscose fibers) have emerged, especially in the textile and clothing industries. The application of flame-retardant rayon fibers is becoming more and more widespread. It can not only improve the safety performance of products, but also meet the comfort needs of consumers. The flame retardants for FR rayon fibers are mainly divided into silicon and phosphorus series. Silicon series flame retardants achieve flame retardant effects by adding siloxane to the rayon fibers to form silicate crystals. Their advantages are environmental friendliness, non toxicity, and good heat resistance, which are usually used in high-end protective products. Phosphorus based flame retardants are used to suppress flame propagation by adding phosphorus based organic compounds to rayon fibers and utilizing the oxidation reaction of phosphorus. They have the advantages of low cost, high flame retardant efficiency, and environmental friendliness, and are generally used in non-woven fabric manufacturing.