The invention discloses health-care black garlic powder, which is prepared by the following raw materials in parts by weight: 100 to 200 parts of black garlic powder, 10 to 15 parts of L-threonine, 5 to 10 parts of proline, 5 to 10 parts of nicotinamide, 8 to 10 parts of leucine, and 3 to 5 parts of glycine. The invention also discloses a preparation method of the health-care black garlic powder. The health-care black garlic powder is prepared by adopting a fermentation mode combined bycombining garlic clove natural fermentation, natural fermentation after smashing and compound bacteria fermentation, so that the fermentation time is short, the product can be fully fermented, a large amount of fermentation time is saved, and the fermentation quality is improved; the L-threonine, the proline, the nicotinamide, the leucine and the glycine are added in the black garlic powder, so that the dissolution rate of allicin is improved, and the nutritive value and the health-care function of the black garlic powder are remarkably enhanced.