The invention discloses a light aggregate. The light aggregate is prepared by the solid raw materials and a water glass solution, the mass ratio of the water glass solution and the solid raw materials is 0.7-1.2:3; wherein, the solid raw materials are composed of industrial wasteland sintering particles, coal ash, slag and a foaming agent, the mass part of the industrial wasteland sintering particles accounts for 20-99% of the solid raw materials, the mass part of the coal ash accounts for 0-50% of the solid raw materials, the mass part of the slag accounts for 0-70% of the solid raw materials, and the mass part of the foaming agent accounts for 0.1-0.5% of the solid raw materials. The light aggregate has the advantages of simple process, no requirement of roasting, low production cost, and less energy consumption, compared with a traditional ceramic light aggregate, the light aggregate is different, a matrix belongs to an alkali-activated gelling material, so that the light aggregate has the advantages of light weight, high intensity, good toughness, low water absorption, good volume stability, excellent alkali resistance, and wear resistant performance.