In this paper, the natural colorant from Vietnam Huyet du leaves were extracted by ultrasound-assisted extraction (UAE) technology using ethanol solutions. Three independent variables including extraction temperature (30-70 °C), ethanol concentration (5-95%) and sonication time (5-45 min) were investigated. The Box-Behnken design (BBD) with the help of Design Expert 10 was used to investigate the effect of process variables on the Huyet du colorantextraction process. Second-order mathematical regression model was developed and matched well with observed data. Response surface methodology (RSM) was performed to find out the optimal condition for total anthocyanin content as follow extraction temperature of 69.85°C,ethanol concentration of 94.15% and sonication time of 30.49 min. In this optimal condition, the total anthocyanin content was determined as 46.43 mg/l extract. The experimental value under optimal condition was in good consistent with the predicted value. In addition, the UV/Vis and FTIR analyses were confirmed that anthocyanin compounds are the major colouring components of Huyet du extract. A rotary evaporator was employed for concentrating Huyet du anthocyanin solution and recovering ethanol solvent.