Abstract: In order to prepare a new kind of natural fibers and analysis its properties, the curaua fiber was extracted by the method of ultrasound-alkali-H2O2 one-bath technology. The four parameters of ultrasonic time, alkali treatment time, the concentrations of NaOH and H2O2 were optimized by multiple indicator orthogonal experimental method based on the evaluation factors of fibers diameter, breaking strength and moisture regain. The basic physical properties, adiathermic property together with the antibacterial property of curaua fibers were evaluated. Further more, the mechanism of adiathermic property and the antibacterial composition were explored. The results show that the optimal parameters were ultrasonic time of 70 min, alkali-oxygen one bath time of 100 min, alkali weight concentration of 8 g/L, hydrogen peroxide weight concentration of 12 g/L in the solution of 0.75 L. The extracted curaua fibers are 47.19 μm in diameter, 152.59 mm in length, 2.03×10?4 MPa in tensile strength and 15.33% in moisture regain, which are comparable with ramie fibers. The curaua/cotton(70/30) net with the CLO value of 1.316 and the thermal resistance of 0.204 m2·K/W, has certain warmth retention property, which is slightly lower than wool fibers net. In vitro antibacterial test，we found that curaua fiber has excellent antibacterial effect to colibacillus and staphylocccus aureus. In addition, the SEM pictures show that there are lumens in the cross section of the fibers. The filter liquor of curaua fiber has flavonoids of antimicrobial substances, which was tested by the ultraviolet spectroscopy.