The invention discloses light environment-friendly heat-preservation mortar which is prepared from the following components in parts by weight: 120-180 parts of ordinary silicate cement, 15-20 parts of foam glass powder, 1.5-2 parts of foam plastic granules, 0.1-0.5 part of hydroxyethyl cellulose, 2-4 parts of redispersible latex powder and 3-5 parts of wollastonite powder. The foam glass powder used in the mortar is made of waste crushed glass, the density of the foam glass powder is less than or equal to 200Kg/m<3>, the foam plastic granules are made of crushed waste foams, and the density of the foam plastic granules is less than or equal to 20Kg/m<3>. The light environment-friendly heat-preservation mortar is low in heat conduction coefficient, resistant to cracking, simple to construct, low in cost and light in volume-weight, the self-weight of a structure is effectively reduced, the burden of a basic load is alleviated, the industrial wastes are sufficiently utilized, the environment pollution problem is solved, the environmental friendliness is achieved, and the energy is saved.