The invention relates to the field of functional coatings and particularly relates to a high-temperature-resisting heat-insulation coating and a preparation method thereof. The high-temperature-resisting heat-insulation coating is composed of the following raw materials in percentage by mass: 10%-40% of high-reflection paint with a shell-core structure, 10%-40% of heat-insulation powder with the shell-core structure, 1%-5% of a toughening agent, 10%-50% of a high-temperature bonding agent, 1%-10% of a coating auxiliary agent, and the balance of water. The preparation method comprises the following steps: mixing, dispersing and grinding raw materials; carrying out homogenization to enable an average grain diameter to be 325-400 meshes; and filtering and packaging to obtain a finished product. The high-temperature-resisting heat-insulation coating can be applied to high-temperature fields of industrial furnaces, industrial boilers, high-temperature steam pipelines, petroleum cracking equipment, engine parts, high-temperature smelting, sintering furnaces and the like, and can be used under a higher temperature for long time; the energy consumption can be saved and the service life of the furnaces is prolonged.