The invention relates to a preparation method of waterborne electromagnetic shielding coating. According to the formulation, the waterborne electromagnetic shielding coating is prepared from, by weight, 10.0-60.0 parts of water, 0.1-0.3 part of wetting agents, 0.4-0.8 part of dispersant, 0.1-0.3 part of defoamer, 0.7-1.3 parts of anti-freezing agents, 0.2-0.5 part of pH modifier, 20.0-60.0 parts of electromagnetic shielding additives, 0.5-2.0 parts of thickener, 25.0-40.0 parts of acrylic emulsion, 0.8-1.3 parts of coalescing agents, 0.2-0.4 part of preservative, 0.3-0.6 part of mould-proof anti-alga agents and 0.1-0.3 part of theological additives. The preparation method has the following advantages that the waterborne electromagnetic shielding coating prepared from graphene / nano ferrite, zinc oxide whiskers, nano silicon carbide, nanometal nickel powder and other materials has the advantages of being light, wide in frequency band, excellent in shielding performance, safe, environmentally friendly and the like, and the requirements of the electromagnetic shielding materials for impedance matching are met.