The precursor of LaMnO3 obtained by the reaction of metal salt with potassium hydroxide was subjected to hydrothermal condition in an autoclave then the precipitate was treated in different temperatures (600-900°C). The effect of precursor type and hydrothermal crystallization conditions on the morphology of lanthanide manganese grains was investigated. The morphology and the structure of the products was studied by transmission electron microscope (TEM) and X-ray diffraction (XRD). Different shapes of LaMnO3 can be obtained by controlling prepare condition and treated temperature. The XRD results showed the formation of perovskite-type LaMnO3.