Abstract: Gingerol was extracted from powder of dry ginger with three different methods of organic solvent, ultrasonic extraction and microwave extraction. The results showed that the yield and purity of the gingerol were the lowest with organic solvent method, 0.15% and 49.7%, respectively. The yield and purity of the gingerol were the best with ultrasonic method, 1.39% and 77.4%, respectively. The extracts of the ginger were characterized with infrared spectroscopy (IR), ultraviolet spectroscopy(UV). By orthogonal experiment, the optimum conditions with ultrasonic method were radiation time 1.5 h, ultrasonic power 500 W, rate of cavitation 0.7. The antioxidation of the extract from powder of ginger was determined. The extract with high antioxidation could efficiently clean out superoxide anion free radical (SARF) and 1,1-diphenyl-2-picrylhdrazyl (DPPH) free radical.

Key words: gingerol, ultrasonic, microwave, antioxidation