Recycled polyester fiber refers to the production of polyester fiber by a series of complex processes using waste old polyester bottle flakes, spinning waste, bubble material, pulp blocks as raw materials. The yarn adopts recycled polyester as the processing raw material, which not only conforms to the sustainable development policy, but also has excellent properties such as strength, moisture absorption, softness, and comfort. The fabric made of this yarn has good shape retention, moisture absorption and drying, and has the advantages of wash resistance and antipilling.