The invention discloses a method for recovering copper ions in acidic copper printed circuit board waste etching liquor and application. Copper ions in the acidic copper printed circuit board waste etching liquor are recovered in a form of copper phenylalanine with high added economic value by a liquid deposition method, the recovered copper phenylalanine serving as a negative pole active materialis applied to a lithium ion battery, and the charge and discharge performance and cycling stability of the product are tested by a constant current charging/discharging method. According to the method, the copper ions in acidic copper printed circuit board waste etching liquor can be effectively recovered, waste materials are changed into things of value, the environmental pollution is reduced, green production of the battery industry and sustainable development of ecological environment can be facilitated, and the preparation process is simple, excellent in repeatability and favorable for batch production.