The invention provides a bag grouting well wall sealing structure. The structure is characterized by comprising a bag and a grouting pipe; the bag is fixed on the outer wall of a well pipe; the bag isconnected with the grouting pipe, and a grouting port of the grouting pipe extends to the ground; after the bag is grouted, the bag is expanded to a hole wall original soil body to be in full contactwith the original soil body or is expanded to be embedded in the original soil body. The bag grouting well wall sealing structure has the advantages that 1, the operation is simple, the effect is reliable, the purpose of well wall sealing can be achieved quickly; 2, the well wall sealing effect can be maximally improved, and the effect of resisting confined groundwater head pressure of the well wall can be improved, thereby ensuring the sealing effect of the well wall a relief well or recharge well.