AgCl powder materials with different morphologies were prepared by ultrasound-assisted dealloying method using Ca-Mg-Cu-Ag amorphous strips as precursors, Cu-Ag nanoporous material as intermediate product, and hydrochloric acid solutions with different solvent compositions as reaction solution. The morphology, structure, and composition of samples were characterized and analyzed using SEM, XRD and other detection methods, and the formation process and mechanism of AgCl / Ag composite powder material were revealed in different reaction solutions. The results show that under ultrasound- assisted, when using hydrochloric acid ethanol solution as reaction solution, Cu-Ag nanoporous material can be completely dissolved in the solution and then different morphologies of AgCl powder material can be reprecipitated form the same solution after changing the volume ratio of concentrated hydrochloric acid solution to ethanol solvent. When using hydrochloric acid aqueous solution as reaction solution, Cu-Ag nanoporous material can only directly transform into nearly spherical AgCl powder material after changing the volume ratio of hydrochloric acid aqueous solution to distilled water solution, which cannot be dissolved in hydrochloric acid aqueous solution first and then reprecipitated form the same solution. With the coexistance of ultrasound treatment and hydrochloric acid ethanol solution for the Cu-Ag nanoporous material, there exists a novel AgCl ‘ formation-dissolution-precipitation’ mechanism, which can be used to accurately control the morphology, structure, and size of the reprecipitated AgCl powder material.