The invention discloses a steel platform tower crane foundation and a construction method thereof. The steel platform tower crane foundation comprises bored piles, steel latticework columns and a steel bearing platform. The steel latticework columns are fixed on the bored piles, and the steel bearing platform comprises four steel beams, wherein two of the four steel beams are lower steel beams, and the other two steel beams are upper steel beams. The upper steel beams are fixed on the lower steel beams to form a #-shaped structure, the lower steel beams are fixed on the steel latticework columns, and a tower crane is fixed on the upper steel beams. The steel platform tower crane foundation has the advantages that the tower crane foundation steel beams are machined in a factory, preformed bolt holes are drilled in a lofting mode according to the sizes of tower crane standard section bolts, and accuracy of the bolt holes is high; on-site assembling and disassembling are convenient, the tower crane can be installed as long as the foundation is installed, and maintenance time of concrete is eliminated; in the foundation disassembling process, only the bots need to be detached for hoisting, concrete does not need to be crushed, and disassembling is convenient; disassembled steel beams can be repeatedly used, and construction cost is saved.