The invention discloses a waterborne epoxy composite cement mortar material. The material comprises a component A, a component B and a component C in the mass ratio being (0.5-1.5): (1-3): (12-18), wherein the component A is a waterborne epoxy emulsion, the component B is prepared from, in parts by weight, 3-10 parts of water, 3-10 parts of a curing agent and 0.01-0.1 parts of a defoaming agent, and the component C is prepared from 30-60 parts of quartz sand, 20-40 parts of cement, 0.1-0.5 parts of a water reducer, 0.2-1.0 part of an additive and 0.1-1.0 part of a defoaming agent. The material is green, environment-friendly and low in cost, has good matching performance in concrete, can be cured in humid interfaces and has reinforcement and permeation resistance functions, the problem that traditional floor coatings peel or have bubbles is solved, the one-time forming thickness can reach 2 mm or above, basic planes are easy to level, and construction is easy. The invention further discloses preparation and construction methods of the material. The preparation condition is mild, the method is simple and suitable for large-scale industrial production, the construction process is simple and feasible, and the construction cost is low.