The utility model relates to a fall horizontal propulsion structural of triangle, it belongs to crossing structure technical field. The utility model discloses a portal, hydro -cylinder, cantilever crane festival and push rod, the hydro -cylinder is fixed on the portal, and the cantilever crane festival is fixed with the portal, and the cantilever crane festival adopts inverted triangle structure,and the piston rod of hydro -cylinder links to each other with the push rod, pushes away this pole and is connected with the cantilever crane festival. The utility model has the advantages of reasonable design, safe and reliable, convenient operation, reducible construction occupation space.