This study examines the growth of nanoporous ellipsoidal hematite via hydrothermal synthesis. Initially, iron oxyhydroxides agglomerate at 30 min, followed by needle-shaped FeOOH formation at 45 min. As the reaction progresses, FeOOH dehydrates and transforms into ellipsoidal hematite. After 120 min, lattice rearrangement results in nanoporous ellipsoidal hematite (~ 27 nm). These findings provide insight into hematite crystal growth mechanisms.