The invention relates to a preparing and applying method for negative oxygen ion microcapsules for fabric. The preparing method comprises the steps of core material preparing, wall material selecting and solution preparing. The preparing method specifically comprises the steps that firstly, raw materials of negative oxygen ions are ground by a grinding miller, the ground raw materials are placed in a certain amount of distilled water and stirred for 0.5-1 hour by an agitator, and a nanometer grinding rod type grinding machine is used for carrying out grinding; secondly, a physical envelope method is adopted, a wall material is prepared into a solution with a certain concentration, a negative oxygen ion nanometer core material, the distilled water and absolute ethyl alcohol are added into the solution according to the proportion, and the mixed solution is stirred under the conditions that the rotating speed is 1080 rmp and the temperature ranges from 40 DEG C to 60 DEG C for 1-3 hours and then is cooled for standing. The negative oxygen ion microcapsules are applied to cotton, fiber, real silk and other fabric. According to the method, the negative oxygen ions with a certain concentration can be released, good packaging and separating performance and slow releasing performance of the microcapsules are utilized to achieve the effects of protecting the core material and lasting releasing, and the detects that traditional negative oxygen ion materials are single in application and not washable overcome.