Abstract: The morphology control and activity evaluation of CuO in the alkali decomposition process of copper-ammonia solution were investigated in this paper. Using copper-ammonia solution and NaOH as raw materials, the influence of feeding mode and feeding speed on the morphology of products was examined through X-ray diffraction, scanning electron microscopy and laser particle size detection, and the mechanism influencing the dissolution activity was explored. By adjusting the feeding method and controlling the initial pH, CuO with either flake-like or needle-like morphology was obtained. The dissolution activity of copper oxide is primarily determined by the grain size, with smaller grains exhibiting more vigorous dissolution activity. When the grain sizes are similar, the dissolution activity is further affected by particle morphology, compactness and particle size. Under the condition of positive addition, copper oxide products with a dissolution rate of less than 30 s can be obtained by controlling the initial NaOH concentration, which meets the dissolution rate requirements specified in HG/T 5354—2018 for active copper oxide powder.