The invention discloses a method for reducing the content of nitrites in pickles and application. The method comprises the following steps of: preparing galacto-mannan-oligosaccharides (GMOS) solution from guar gum serving as a raw material by a beta-mannase enzyme process, wherein the enzymolysis rate of the guar gum is between 12 and 24 percent, and the average degree of polymerization of the product is between 4 and 6; and cutting vegetable raw materials into blocks, cleaning, disinfecting, draining, adding sterilized saline solution and the GMOS solution, inoculating lactobacillus plantarum thalli, and fermenting to obtain the pickles of which the content of the nitrites is reduced. In the method, oligosaccharides are added, so that lactobacillus plantarum is fermented quickly to produce acid, the total number of mixed bacteria is reduced, the fermentation period is shortened, the nitrites are degraded, and the safety of the pickles is improved. Compared with the conventional pickle fermentation, the method has the advantage that: the GMOS is added into the pickles, so that the conventional excellent flavor of the product is kept, the fermentation period is shortened by over 24 hours, the content of the nitrites in the finished product is 23 percent, and an effect is obvious. The method can be widely applied to the preparation of the pickles.