Provided are a method for producing a lithium secondary battery thick film and a method for producing a lithium secondary battery, by using electrostatic slurry spraying of slurry containing a sulfide-based solid electrolyte. Particularly, the method for producing a lithium secondary battery thick film comprises: a step of preparing slurry in which the powder of a sulfide-based solid electrolyte is mixed with at least one solvent selected between a dichloroethane and a dichlorobenzene, at the weight ratio of 1:10 to 1:100; and a step of depositing a lithium secondary battery thick film by electrostatically spraying the slurry on a current collector under a nitrogen atmosphere in the cone-jet mode.