The purpose of this study is to develop a new preparation process of American ginseng (Panax quinquefolium) extract featuring high concentration of ginsenoside $Rg_3$, $Rg_5$, and $Rk_1$, Red ginseng special components. Chemical transformation from ginseng saponin glycosides to prosapogenin was analyzed by the HPLC. Extracts of American ginseng were processed under several treatment conditions of microwave and vinegar (about 14% acidity). The results showed that the quantity of ginsenoside $Rg_3$ increased by over 0.9% at the 20 minutes of the pH 2~4 vinegar and microwave American ginseng ethanol extract compared with other process times. The result of MAG-20 indicates that the American ginseng microwave and vinegar-processed American ginseng extracts (about 14% acidity) treated for 20 minutes produced the highest amount of ginsenoside $Rg_3$ (0.969%), $Rg_5$ (1.071%), and $Rk_1$ (0.247%). Besides, MAG-15 indicates that the microwave - and vinegar-processed American ginseng extracts (about 14% acidity) treated for 15 minutes produced the highest amount of ginsenoside $Rg_3$ (0.772%), $Rg_5$ (1.330%), and $Rk_1$ (0.386%). This indicates that American ginseng treated with microwave and vinegar had the quantity of the ginsenoside $Rg_3$ over 32 times the amount of the ginsenoside $Rg_3$ (which was not found in raw and American ginsengs) in the average commercial Red ginseng.