Abstract To develop antibacterial durability and low yellowing of sports underwear fabric, silver ion polyurethane filaments (Ag+ PUFs) were used as base yarn, and polyamide filaments were used as face yarn. Nine fabric samples with different Ag+ PUF contents (7, 8, 9, 17, 18, and 19%) were prepared. The fabrics were dyed in light, medium, and dark pink. Ag+ PUF was characterized by scanning electron microscopes for the morphology. Antibacterial properties and mechanical properties of Ag+ PUF were measured. The antibacterial durability, yellowing, elastic recovery, air, and moisture permeability were tested, and fuzzy mathematics was used for comprehensive evaluation. The results demonstrated that Ag+ PUF has good antibacterial properties and mechanical properties. The inhibition rates of the fabric against Escherichia coli and Staphylococcus aureus were 100%. When Ag+ PUF content was 18 and 19%, the antibacterial rates of medium pink fabrics both E. coli and S. aureus were 100% after laundering 30 times. The yellowing of the fabric before dyeing was the lowest when Ag+ PUF content was 7%. Compared with before dyeing, the yellowing of the fabric decreased by 19.13 % after dyeing. The comprehensive performance of 3# fabric is the best, and it has antibacterial persistence and low yellowing.