Hierarchical nanostructures β-FeOOH and α-Fe 2 O 3 with different morphology were successfully synthesized via a facile and green hydrolysis-aging method using urea or saccharide as organic matrix. Experimental results showed that the well crystallized β-FeOOH and α-Fe 2 O 3 could obtain without higher temperature processing. Systematic control on the morphology and microstructure of the products was achieved by regulating the aging time and the concentration of organic matrix.The amount of saccharide was very important in stabilizing metastable β-FeOOH.The formation mechanism of various morphologies and the cause of stabilizing β-FeOOH were tentatively proposed on the basis of the evolution of the structure and the morphology, along with variation of the reactive conditions. Also, degradation efficiencies of the α-Fe 2 O 3 and β-FeOOH with different morphologies toward methylene blue were preliminarily investigated, revealing that as-obtained α-Fe 2 O 3 and β-FeOOH possessed promising photodegradation activity and had potential application in wastewater treatment. spray pyrolysis method [25] , liquid phase-based ultrasonic-assisted method [26] , biphasic interfacial reaction [27] , thermal decomposition process [28] , chemical precipitation reaction [29] , biomimetic synthesis [30] , and so on.Akaganeite (β-FeOOH) is also an important kind of iron oxides semiconductor with a band gap of 2.12 eV. Likewise, β-FeOOH has attracted much attention because of its channel-type nanoporous structure and unique sorption, ion exchange, and catalytic properties [31][32][33][34] . On other hand, β-FeOOH is always served as a precursor in the preparation of ferromagnetic α-Fe 2 O 3 because of its thermodynamic metastable