Bio-based PTT is a green degradable polyester material which can be prepared by the polymerization with biobased1,3-propylene glycol (PDO) and terephthalic acid (PTA). In the present work, a bio-based polytrimethyleneterephthalate (PTT) antibacterial fabric was fabricated by a traditional dyeing method using a natural acid mordant dye andmetal ion. The color of madder dye is sensitive to the outside environment. Different metal ions have great influence on thecolor of madder dye, which can not only enrich the chromatogram of plant dyes but also improve the dyeing fastness. Furthermore, Bio-based PTT fabric can be dyed with the madder dye under atmospheric dyeing condition by one-bath andoptimal Dyeing Conditions were 90-100 oC of dyeing temperature, 40 min of dyeing time and 5-6 pH of dye solution. Theantimicrobial test results showed that the dyed PTT fabrics dyed with only madder dye exhibited good antimicrobialproperties. In the dyeing process, the introduction of metal silver ion to dyed PTT fabrics enhanced antimicrobial propertiesand washing fastness. Madder-Ag+ dyed PTT fabric in one bath medium displayed excellent inhibitory effect on the growthand reproduction of S. aureus and E. coli. After 10 times of washing, it still possessed excellent antibacterial performance,and the antibacterial rate still reached 99 %. In our work, the traditional one-bath dyeing method with natural acid mordantdyes and Ag ions can realize coloring and antibacterial properties. The functional application of bio-based PTT materials willbe expanded.