Provided are an electrolytic copper foil, an electrode comprising the same, and a lithium ion battery comprising the same. The electrolytic copper foil has a drum side and a deposited side opposing to the drum side, wherein a nanoindentation hardness of the drum side is equal to or larger than 0.5 GPa and equal to or smaller than 3.5 GPa; and a lightness of the drum side is equal to or larger than 25 and equal to or smaller than 75.