Rayon-spandex blended fabric, renowned for its ability to stretch 5 to 8 times without losing elasticity, ensures both comfort and durability while exhibiting excellent anti-aging capabilities. Notably, spandex, as a key component, cannot independently form fabric but is usually intricately blended with high-quality rayon and other materials. The spandex content is carefully controlled between 3% and 10% to optimize fabric performance; particularly in swimwear fabrics, the spandex content can reach up to 20% to meet the ultimate demands for elasticity and fit. Spandex fiber, a high-performance synthetic fiber, is known for its elongation at break of over 400%, low modulus, and high elastic recovery rate, also referred to in the industry as multi-segment polyurethane fiber or elastic fiber. Its characteristics include an astounding elongation range (500% to 700%), softness under low stress (e.g., at 200% elongation, the modulus is only 0.04~0.12 g/denier), and near-perfect elastic recovery (with a recovery rate of 95% to 99% after 200% elongation), all of which collectively establish the foundation for high-quality fabric. In addition to the remarkable high strength, rayon-spandex knitted fabric shares many physical and mechanical properties with natural latex yarns, while surpassing them in chemical stability, showing good resistance to chemical degradation and suitable thermal stability, with a softening point set at 200°C or higher, ensuring wide adaptability in processing and use. In the dyeing and finishing stages, the dyes and finishing agents we use are widely compatible with both synthetic and natural fibers, making them equally suitable for the meticulous treatment of rayon-spandex knitted fabrics, ensuring color richness and overall fabric quality. Furthermore, this fabric has excellent resistance to perspiration, seawater, various dry-cleaning solvents, and most sunscreens. Although prolonged direct exposure to sunlight or frequent contact with chlorine bleach may cause slight fading, the fading performance varies among different types of spandex. We have implemented multiple technical measures to minimize this impact, ensuring the product remains as good as new for an extended period.