The controlled synthesis of inorganic materials with desired morphologies and architectures at micro- and nanoscale levels is of great importance to inorganic material design. In this study, we describe an innovative morphology control concept named anions competition method. The key point is to introduce another concomitant raw material to not only share the total demand of cations but also provide competitive anions required by the morphology control. Take boehmite for example, aluminum sulfate was consciously and proportionally introduced as another concomitant raw material into aluminum chloride/aluminum nitrate-urea hydrothermal process to form SO42--Cl- and SO42--NO3- competition systems. Boehmite from lamellar assemblies to hollow microsphere morphologies was facilely synthesized by succinctly altering the relative proportion of SO42-:Cl- and SO42--NO3-. (C) 2013 Elsevier B.V. All rights reserved.