The invention relates to fermentation technology for high-activity black garlic. The fermentation technology has the technical key points that: fresh garlic is packaged into a heat-resistant plastic food bag, and is added with garlic oil and sealed for natural fermentation; and after the fermentation is finished, the garlic is subjected to vacuum drying treatment to form a high-activity black garlic product. The finished product black garlic prepared by the technology has the characteristics of high beneficial component content, stable product performance, no added additives, small stimulation, good mouthfeel and easy preservation; in the technology, soaking technology in the conventional fermentation technology for the black garlic is saved, so that the processing technology is simple, the fermentation process avoids humidification, and the equipment cost is saved; the garlic oil and active components contained in the garlic are converted into functional components such as ajoene, polyphenol and the like by utilizing a principle of enzyme fermentation of the garlic, so that the active component content of the garlic are improved greatly; and the fermentation process does not discharge odor such as sulfide odor and the like, so that the working environment is improved greatly.