A simple aqueous Solution route was introduced for the fabrication of CuO pricky microspheres (CPMs) using CuCl2.2H(2)O, Na-2(C4H4O6)-3H(2)O and NaOH as starting materials. The CPMs were composed of compressed nanothorns exhibiting tapering feature with tip size of less than 10 nm, and the size of CPMs could be tuned from 100-200 nm to 4-6 mu m. The effects of the molar ratios of tartrate anions and NaOH to Cu2+ cations, reagent concentration, and reaction temperature on the products were investigated, showing that the morphology of CPMs was determined by the molar ratio of tartrate to Cu2+ cations and the size was greatly affected by reagent concentration and the molar ratio of NaOH to Cu2+ cations in the precursor solution. The fabrication of CPMs went through rapid nucleation of Cu(OH)(2), aggregation and in situ dehydration of Cu(OH)(2), oriented-aggregation-based growth, and normal crystal growth of CuO nanothorns. The nucleation and crystal growth were successfully separated by controlled releasing of Cu2+ and OH-ions through the reversible reaction of Cu2+ cations, OH-, and C4H4O62-anions.