Self-oriented Ca3Co4O9 nanoflake thin film has been prepared by a simple sol-gel method as the anode for thin-film lithium-ion batteries. The X-ray diffraction and transmission electron microscopy results show that the prepared Ca3Co4O9/Pt film is c-axis self-oriented and composed of nanoflakes approximately 2 mu m in diameter and 200-300 nm thick. The reversible lithium storage capacity of the Ca3Co4O9 thin-film electrode at 1 C is around 800 mAh g(-1), and it retains more than 70% capacity after 50 cycles, suggesting that the Ca3Co4O9 thin film can be used as the anode for lithium-ion batteries.