The invention provides a high-altitude construction method of a multi-layer long-span heavy-load concrete structure. The combination of an intelligent lifting tool type template supporting steel platform and an intelligent monitoring system, reserved construction from the top to the bottom is conducted on the horizontal structure in the multi-layer long-span heavy-load concrete structure, the mainconstruction method includes the following steps that the high-altitude long-span heavy-load tool type template supporting steel platform and a template supporting rack are integrally combined on theground, the vertical structure of a body is constructed to a preset elevation in advance, a temporary bearing point is arranged on the vertical structure of the body, intelligent lifting machinery ismounted on and fixedly connected with the temporary bearing point of the body structure, after preloading load verification is conducted on the ground, intelligent control automatic overall synchronous lifting is conducted, reserved construction from the top to the bottom is conducted on the horizontal structure of the body, and platform automatic synchronous falling is conducted. The high-altitude construction method of the multi-layer long-span heavy-load concrete structure has scientific principle, ingenuity methods, advanced technology and is safe, reliable and simple and convenient in technology, the construction period is shortened, the cost is lowered, and labor intensity is lightened. Combined with the intelligent monitoring system, active safety, in the construction process, of the horizontal structure of the body is realized.