The present invention relates to a gel polymer Li-ion battery electrode slice and a method for preparing the same. The electrode slice comprises a two-layer composite structure of electrode active material/gel electrolyte or a three-layer composite structure of electrode active material/gel electrolyte/electrode active material. The method includes preparation and filtration of gel polymer Li-ion battery electrode slurry and gel polymer electrolyte slurry and a multi-layer one-step coating process, and includes the following steps: a) grinding an electrode active material, and adding an adhesive, a surfactant, a dispersant thereto to obtain a raw slurry of the electrode active material; b) filtering the raw slurry of the electrode active material to obtain a uniform, fine precoating slurry; c) dispersing a monomer, a curing agent of the gel electrolyte and a polymer Li battery electrolyte into a solvent, and filtering the resultant dispersion to obtain a precoating gel electrolyte slurry; and d) coating directly the precoating slurries obtained in steps b) and c) on a composite film of current collector and polyester by a multi-layer one-step coating process to obtain a battery electrode slice of a two-layer composite structure of electrode active material/gel electrolyte or of a three-layer composite structure of electrode active material/gel electrolyte/electrode active material.