The invention provides a lobby large-span folded beam construction method. The lobby large-span folded beam construction method sequentially comprises the following steps that temporary support pre-embedded parts are embedded, floorslab concrete of the layer is poured, temporary supports are assembled, the temporary supports and the pre-embedded parts are welded, cable wind ropes are bound on thetemporary supports and the ground, a top jack is placed, a first steel beam is hoisted, outdoor pillars are hoisted, a second steel beam is hoisted, a third steel beam is hoisted, the elevation positions of the steel beams are measured and adjusted through a total station, the steel beams are welded, the jack is unloaded, and large-span folded beams are mounted. Compared with the related technology, the lobby large-span folded beam construction method has the following advantages that construction of large-span and large-height Z-shaped beam mounting is achieved, and meanwhile, safety qualityis ensured through the overall construction process.