The invention provides exterior wall latex putty and an application of a water-based paint solid waste in the exterior wall latex putty. The exterior wall latex putty is prepared from a dispersing agent, an antifoaming agent, a bactericide, the water-based paint solid waste, a polishing agent, an emulsion, a coalescing agent, an anti-freezing agent, a water-retaining agent, a pH value modifier and a thickener. The exterior wall latex putty has the advantages that (1) the exterior wall latex putty is prepared from the water-based paint solid waste, so that secondary recovery of industrial wastes is achieved, the economic benefits are generated and emission of industrial solid wastes is reduced; (2) the exterior wall latex putty is low in cost and high in economic benefit; (3) the exterior wall latex putty is simple and convenient in construction and easy to polish; and (4) the exterior wall latex putty is high in bonding strength, high in flexibility and wide in application prospect in exterior wall coating construction.