The invention relates to a treating method for a geological crushed zone of an underground water sealing cavern storage cavern area. The treating method comprises the following steps that the characteristics of the geological crushed zone are determined by combining with data of the geology and exploration holes; grouting grout, the technology and the termination standard are determined, through grouting holes, pre-grouting is conducted on the geological crushed zone and rock-soil bodies around the geological crushed zone, a water-stop curtain is formed, the crushed zone is reinforced, and grouting effect detection is conducted; blasting excavation is conducted till the geological crushed zone is exposed, and then the rock-soil bodies, away from the periphery of a cavern within a certain range, of the crushed zone are excavated out and replaced with concrete for filling; the contact surfaces between the concrete and the rock bodies as well as between the concrete are grouted, and the grout, the technology, the termination standard and the effect detection standard which are the same as those of pre-grouting can be adopted; and after construction of a supporting structure is completed, a surrounding rock deformation detecting part is arranged on the surface layer of the original geological crushed zone, and whether a shotcrete and bolt support needs to be reinforced or not is judged. According to the treating method, the difficult problems of water plugging and reinforcing of the geological crushed zone of the storage cavern area can be solved, the step is simple, construction is easy and convenient, the investment cost is saved, and the treating time is short.