Iron oxide (hematite, $alpha$-${Fe}_{2}{O}_{3}$) particles were prepared directly from aqueous solution using a crystal growth controller. Paticles properties and reaction mechanisum of products as a function of basicity, formation process and mechanism of needle-lkie hematite were investigated. hexagonal hermatite particles were formed in teh range below pH 9.0, ellipsoidal or rectangular hematite particles in the range of pH 10.75-11.75 respectively. In the range above pH 12.50, acicular $alpha$-FeOOH was formed. Basicity of product solution produced in the range of pH 10.7511.75 was increased slightly as compared with basicity of reastants due to hydroxly ion(OH-) formed by dissociation crystal growth controller. Citric acid which is acted as a crystal growth controller was adsorbed in the form of itrate anion(R-COO-) on the ferric hydroxide and exerted important role on the formation to the needle-like $alpha$-${Fe}_{2}{O}_{3}$ particles in this reaction system.