The present invention discloses an auxiliary equipment for member mounting construction in hydraulic engineering and its use method. The described auxiliary equipment is placed on the water surface around the member body or under water surface or can be placed under water surface in interior cavity body of said member body. It includes more than one floatation aiding mechanism and positioning connecting component connected between said floatation aiding mechanism and member body. The described floatation aiding mechanism includes air bag, balloon, glass water ladle, inflatable tyre, tyre, sealed bin, wooden boat body, inflatable rubber dirigible and wood and plastic body or steel sealed tank. Besides, said invention also provides the application method of said auxiliary equipment. |