Disclosed is a constant-temperature insulation steel silo. A common steel silo is already widely used as being low in cost and fast in construction and is unsuitable for long-term storage of grain and only suitable for revolving as not having an insulation function. The constant-temperature insulation steel silo is composed of a foundation (1) and a silo body (2) connected with the foundation, an insulation layer (3) is fixed to the outer side of the silo body through connectors, a peripheral plate (4) is fixed on the insulation layer or the silo body through supports, and the insulation layer and the peripheral plate form an air heat-insulation course. The constant-temperature insulation steel silo is used as a granary for long-term grain preservation.