We studied a novel bioﬂocculant poly(γ-glutamic acid) (PGA). With the addition of 4mg/L PGA (Mw=9×105Da) and 12 Mm CaCl2, the optimal temperature for ﬂocculation performance of PGA in the kaolin suspension was about 30°C, giving the highest ﬂocculating activity of 98%, respectively. Studies of the ﬂocculating properties revealed that it was stable at 30-90°C and pH 7-11. With treatment of jean dyeing wastewater flocculation, PGA showed that the color, COD, NH3-N, alkalinity and hardness removal ratios were 90%, 91.7%, 73.3%, 65 % and 86 %, respectively. Bioﬂocculant PGA may ﬁnd possible application as an alternative for textile dyeing industry and environmental bioremediation.