An ink used for direct inkjet printing to plate based on nanometer material and a method for preparing same. Of the baseline total amount of the ink, 5 to 30 wt % is of film-forming resin, 0.01 to 5 wt % is of nanometer or micrometer dye, 30 to 60 wt % is of organic solvent, 0.01 to 5 wt % is of humectant, and water provides the balance; these ingredients are stirred and mixed at room temperature, and after the film-forming resin is completely dissolved, impurities and/or insoluble substances in the present invention are removed by means of multi-level filtering, and the obtained filtrate is the present ink. The ink in the present invention is sprayed on a metal base material surface by an inkjet printer o form a printing pattern which, after curing, can be directly printed on the machine, thus reducing chemical pollution and post-processing processes, while a press run of the printing plate can be up to 100,000 copies at a resolution of up to 175 lpi.