The invention relates to a preparation method for a graphene nanometer screen. The preparation method comprises the following steps: preparing a graphene oxide (GO) aqueous solution by adopting a Hummers method firstly, freezing the GO aqueous solution with a certain concentration in a freezing chamber of a refrigerator to obtain a GO ice block; then preliminarily crushing the ice block into small blocks, putting in a pipe, and freeze-grinding the GO ice blocks in the presence of liquid nitrogen by adopting a freeze-grinding machine; and cooling to room temperature to obtain a GNMs aqueous solution, and carrying out a series of structure characterization. As no chemical reaction happens and no agent is needed in the whole preparation process, the preparation method is a physical method without any pollution and damage to the environment, the preparation method is a true environmental-friendly preparation method. In addition, the preparation method is simple and feasible in operation process, good in repeatability, rich in raw material source and low in cost and has good application prospect.