The present invention relates to a copper alloy production method and a method for manufacturing foil from a copper alloy, and the copper alloy production method of the present invention includes: a metal oxide preparing process of preparing at least two metals, including copper, each of which is in the form of a metal oxide, a nano powder producing process of pulverizing the metal oxides to produce metal oxide nano powder having a nano size, and an alloy producing process of heat-treating the metal oxide nano powder to produce an alloy, whereby, when a copper alloy is produced, precipitates can be minimized, the characteristics of the alloy can be optimized, and the generation of oxides on the outer wall of a molten metal furnace can be suppressed.