Construction method of slanting cantilever steel structure supported by temporary steel frame

Provided is a construction method of a slanting cantilever steel structure supported by a temporary steel frame. The construction method is characterized in that when a slanting cantilever steel truss (7) is installed, the steel frame is adopted to build a temporary support structure, the slanting cantilever steel truss (7) is split into a plurality of hoisting units to be hoisted in sections, temporary supports are arranged below section knotpoint positions, a conversion structure (4) is arranged on the upper portion of the temporary supports, the slanting cantilever steel truss (7) is hoisted in non-stressed state and then assembled in welding mode, and finally the conversion structure (4) and the temporary supports are demounted. The construction method remarkably reduces whole journey independence on a hoist in the prior art, simultaneously greatly improves control conditions of construction accuracy quality, improves truss accurate in place and installation accuracy, ensures project quality and mounting and demounting safety, has the advantages of being simple and convenient in structure, high in stable performance, safe and reliable, quickens construction, and is suitable for being used in large-span, large-weight and large-inclination cantilever steel structures and applicable to construction of the cantilever steel structures mounted and demounted in upper air in sectional welding mode.