Underground water circulation well in-well packer and using method thereof

The invention relates to an underground water circulation well in-well packer and a using method of the underground water circulation well in-well packer. The in-well packer comprises a central pipe, a packing assembly and a driving assembly, the packing assembly is arranged on the central pipe, and at least part of the packing assembly can move relative to the central pipe; the driving assembly is connected with the packing assembly and can drive at least part of the packing assembly to move relative to the center pipe, and when the packing assembly moves relative to the center pipe, the packing assembly can deform to change the size of the cross sectional area. And the packing assembly is contacted with and separated from the inner wall of the circulating well based on the change of the cross sectional area so as to finish the setting and unsetting processes. The using method comprises the steps that the in-well packer is arranged between a water pumping pipe and a water injection pipe; an upper screen pipe