NOVELTY - Substrate is placed on working plate surface at 200-500 degrees C, liquid spray gun (A) is filled using precursor solution (S1) and injected onto the substrate. Solid electrolyte containing borophosphate ion/trivalent aluminum ion-doped lithium and lithium-lanthanum zirconate is mounted on hopper of high velocity oxygen fuel (HVOF) gun (B), and solid electrolyte is injected on substrate. Precursor solution (S2) is filled in the gun and injected onto substrate. The working plate surface is cooled and processed in muffle furnace at 600-900 degrees C for 5-10 hours, to obtain all-solid thin-film lithium battery.    USE - Preparation of thin-film solid-state lithium-ion battery (claimed).    ADVANTAGE - The method provides thin-film solid-state lithium-ion battery having high electrochemical property.    DETAILED DESCRIPTION - Substrate is placed on working plate surface at 200-500 degrees C, liquid spray gun (A) is filled using precursor solution (S1), spray gun (A) is placed perpendicular to surface at distance of 8-20 cm, gun (A) forms angle of 50-85 degrees with heating surface of the working plate and at same time, negative voltage is maintained at 40-80 kV. Carrier gas pressure in gun (A) is maintained at 10-30 kPa, and solution (S1) in the spray gun (A) is injected onto the substrate for 1-30 minutes with injection flow rate of 1-10 mL/minute. Solid electrolyte containing borophosphate ion/trivalent aluminum ion-doped lithium and lithium-lanthanum zirconate (Li7La3Zr2O12) in weight ratio of 1:10:20 is mounted on hopper of HVOF gun (B), combustible gas in the gun (B) is ignited, ratio of combustible gas and oxygen is adjusted, such that flame glows bright blue light, gun (B) is placed perpendicular to surface at distance of 15-30 cm, gun (B) makes angle of 70-90 degrees C with heating surface of the working plate, and solid electrolyte is injected on substrate for 1-10 minutes with injection flow rate of 10-30 mg/minute. Precursor solution (S2) is filled in the gun (A), gun (A) is placed perpendicular to heating surface at distance of 8-20 cm, gun (A) forms angle of 50-85 degrees with heating surface of the working plate, negative voltage of 40-80 kV is applied between gun (A) and substrate, carrier gas pressure in gun (A) is maintained at 10-30 kPa, and precursor solution (S2) is injected onto substrate with flow rate of 1-10 mL/minute for 5-30 minutes. The working plate surface is cooled and processed in muffle furnace at 600-900 degrees C for 5-10 hours, to obtain all-solid thin-film lithium battery containing borophosphate ion/trivalent aluminum ion-doped lithium vanadate/lithium (LiV3O8/Li:BPO4/Al3+Li7La3Zr2O12/Li4Ti5O12).