The invention discloses a piece of waterborne copy paper and a preparation method thereof. The waterborne copy paper is prepared from the following components in parts by weight: 20-55 parts of reed pulp, 4-9 parts of a vinylon binder, 33-66 parts of wood pulp, 1-10 parts of a dispersing agent, 10-18 parts of synthetic resin, 3-5 parts of phloem fibers, 5-25 parts of titanium dioxide, 1-7 parts of carbon black, 7-15 parts of polyvinyl alcohol, 10-13 parts of kaolin, 1-3 parts of resin glue, 1-3 parts of glycerine, 0.3-0.7 part of salinized sodium, 1-3 parts of polyvinyl acetate emulsion, 0.5-3 parts of white nano pigment pulp, 0.7-1.9 parts of a solidifying agent and 0.1-0.8 parts of a crosslinking agent. The waterborne copy paper adopts reed pulp, wood pulp and phloem fibers as main raw materials when being prepared, and the vinylon binder, titanium dioxide, the crosslinking agent and various dispersing agents are combined, so that the prepared waterborne copy paper has high bending strength, small deformation, good colour fastness and good colour saturation stability; and a protective layer is increased on a developing mixture of the paper, the copy paper can be repeatedly used for multiple times, and effect of the developing mixture cannot be influenced.