The invention discloses a high-rise cantilever conversion spatial frame structure construction method. The method comprises the following steps that (1) surveying and setting out are conducted and the installation positions of supporting jig frames are determined; (2) common supporting frames are erected below an upper-portion main structure and the supporting jig frames are installed at the position of a cantilever structure; (3) a first layer of concrete of the main structure provided with the cantilever structure is poured, (4) after the strength of the first layer of concrete of the main structure provided with the cantilever structure reaches designed strength, the common supporting frames are dismantled, and the rest of concrete of the main structure provided with the cantilever structure is poured, (5) after all the concrete of the main structure provided with the cantilever structure is constructed and the strength of all the concrete reaches the designed strength, the supporting jig frames are dismantled and concrete of the rest of the upper-portion main structure is poured until construction is finished. The supporting jig frames are used for converting a large spatial cantilever conversion structure into a non-cantilever structure, the stress situation in the structure construction process is optimized, the investment of a large number of transfer materials is saved, the construction period cost is lowered and the construction period is shortened.