Exterior wall insulation board

The invention discloses an exterior wall insulation board. The exterior wall insulation board consists of a decorative finish layer, a surface cover layer, an insulation layer and a bonding layer which are sequentially connected, wherein the insulation layer is prepared from the following components in parts by weight: cement, coal ash, coal gangue, perlite, talcum powder, ceramsite, foamed glass, sawdust, a water repellent, an early strength agent and a foaming agent; and the components are uniformly mixed, added with water, and subjected to foam preparation, foam stabilization, pouring, static curing, de-molding, curing, cutting and detecting, thereby preparing the exterior wall insulation board. The exterior wall insulation board is light, thermal insulating, soundproof, good in nail absorbing effect, capable of being cut, sawed and dug, high in construction speed and long in service life; leftovers of a glass formed insulation material are matched with the cement, the ceramsite and the coal ash, so that the production cost is reduced, resource waste is reduced, and ecological environment is protected; compared with existing EPS (expandable polystyrene) particles, the exterior wall insulation board is smaller in weight, lower in water absorption, good in affinity with cement, soundproof and more ideal in energy-saving effect, and has strength which is far greater than that of conventional EPS particles.