In this study, different aluminas were obtained by precipitating Al(NO3)3·9H2O with different concentration of aqueous solution of ammonium carbonate. The obtained aluminas were treated by 50 (vol/vol) % ammonia via low temperature immersing and high temperature hydrothermal treatment, respectively, then, the treated aluminas were calcined again. The crystal types, morphology, textural properties, and pore distribution of the original alumina, ammonia-treated alumina, and the second calcined alumina were studied by characterizations of X-ray diffraction, thermogravimetric analyses, nuclear magnetic resonance, Brunauer-Emmett-Teller (BET), transmission electron microscopy, and so on. Several modified aluminas with specific morphology, desired pore structure, and pure crystal types were obtained, which can be used in some specific industrial application.