The invention provides a construction method ofgallerybridge steel structure, which is used for solving the problem that the construction difficulty of a suspended gallery bridge in the prior art is large, comprising the following steps: (1) pouring a concrete platform at the edge of the mountain body, respectively arranging a supporting base and a fixing plate on the concrete platform, a tower column is arranged on the supporting base, and one end of the stay cable is arranged on the tower column; (2) a guardrail is arranged on the right side of the concrete platform, a transportation truss is hoisted by a crawler crane, a connecting plate is arranged at both ends of the truss, a guide rail I is arranged at the top of the truss, a guide rail II is arranged at the lower part of the truss,and the connecting plate and the fixing plate are welded and fixed, a hanging basket is assembled on the right part of the concrete platform, and the traveling wheel of the hanging basket is arrangedon the guide rail II after the assembly is finished; The method not onlyenablesthe suspended gallery to be quickly constructed, but also effectively avoidssituation of falling objects in the construction process.