The utility model relates to a heat preservation structure of an outdoor water supply pipeline in a severe cold area, which belongs to the technical field of water conservancy, hydropower and civil engineering and comprises a nano flame-retardant self-temperature-control ribbon heater, an asbestos tube shell heat preservation layer, a glass cloth wire fixing layer and a tin foil adhesive tape outer heat insulation layer. The nano flame-retardant self-temperature-control ribbon heaters cling to the outer wall of the water supply pipe and are uniformly distributed along the radial direction of the water supply pipe; wherein each nano flame-retardant self-temperature-control ribbon heater is provided with a leakage protector and a control switch, the nano flame-retardant self-temperature-control ribbon heaters are fixed by ribbons, the nano flame-retardant self-temperature-control ribbon heaters are wrapped by the asbestos tube shell thermal insulation layer and are wound and fixed by glass cloth wires, and the glass cloth wires form a glass cloth wire fixing layer; the tin foil adhesive tape outer heat insulation layer wraps the glass cloth wire fixing layer; according to the utilitymodel, the water delivery pipe is uniformly heated, the safety is higher, the heat preservation effect is good, and the operability is stronger.