The invention relates to the technical field of preparation of functional coating, and provides a formula of solvent-free thermal-spraying environment-friendly heavy anti-corrosion coating which is quick to cure, energy-saving and environment-friendly, tough and wearable, strong in adhesive force, good in shock resistance and excellent in corrosion resistance and a preparation method of the coating. Each composition of primary lacquer comprises liquid epoxy resin, an active diluent, auxiliaries, an anti-rusting pigment, a pigment, a filler and a thixotropic agent; each composition of a curing agent comprises amine resin, an active diluent, an anti-rusting pigment and a filler. The preparation method of the coating comprises the following steps: (1), preparing primary lacquer, wherein the liquid epoxy resin, the active diluent and the auxiliaries are taken and added into a cylinder for stirring while the anti-rusting pigment, the pigment, the filler and the thixotropic agent are added to be uniformly dispersed, and then grinding and filtering; (2), preparing the curing agent, wherein the amine resin, the active diluent, the thixotropic agent and the filler are added into the cylinder in sequence for dispersing at low speed and then dispersing at high speed and filtering; and (3), carrying out mixed construction on the primary lacquer and the curing agent by adopting a double-component airless sprayer to form a coating layer.