Disclosed is a method for preparing a water-soluble natural nitric oxide. The method comprises the following steps: S1, selection of raw materials: selecting raw materials comprising plant proteins having large quantities of arginine, washing the raw materials, comminuting the cleaned raw materials, and storing the comminuted raw materials in a fermentation room for later use S2, cultivation of a beneficial bacteria complex: selecting a plurality of beneficial bacteria for plant fermentation, mixing the beneficial bacteria at a predetermined ratio, and cultivating the beneficial bacteria to obtain the beneficial bacteria complex and S3, inoculation and fermentation: inoculating the beneficial bacteria complex obtained in S2 into the raw materials obtained in S1 and adding water, and allowing fermentation at constant temperatures of 28-30˚C to obtain a large quantity of the water-soluble nitric oxide. The method significantly differs from a fermentation process of the prior art. Firstly, the selection of raw materials is very important. Secondly, inoculation is performed using particular beneficial bacteria developed and maintained by the applicant, and fermentation is conducted for a predetermined length of time to produce and store a large quantity of the water-soluble natural nitric oxide. A fermentation broth produced by the fermentation comprises abundant enzymes, and can be consumed to ameliorate a blood vessel-related disease such as hypertension, diabetes, cerebral infarction, and the like.La présente invention décrit un procédé de préparation dun oxyde nitrique naturel soluble dans leau. Le procédé comprend les étapes suivantes : S1, sélection des matières premières : sélection de matières premières comprenant des protéines végétales présentant une grande quantité darginine, lavage des matières premières, broyage fin des matières premières nettoyées, et stockage des matières premières finement broyées dans une pièce de fermentation pour utilisation ultérieur
