The disclosure provides a preparation method of a porous copper alloy wick, including the steps of: a) preparing an electrolyte, which is an aqueous solution including 0.5-1.8 mol/L sulfuric acid and 0.1-0.5 mol/L copper sulfate; b) cleaning with a mixed solution of a surfactant and a basic compound, activating with dilute hydrochloric acid and then cleaning the surface of a copper alloy substrate; c) forming a porous structure on the substrate by electrodeposition on the treated substrate in the electrolyte; and d) washing with water, drying and then sintering the product obtained in step c). By the method of the disclosure, the porous structure with the specific arrangement, excellent capillary force and permeability can be directly obtained on the surface of the substrate, which is good for the transmission of the working liquid.