Hierarchical dendritic micro–nano structure Zn Fe_2O_4 have been prepared by electrochemical reduction and thermal oxidation method in this work. X-ray diffractometry, Raman spectra and field-emission scanning electron microscopy were used to characterize the crystal structure, size and morphology. The results show that the sample(S-2) is composed of pure ZnFe_2O_4 when the molar ratio of Zn~(2+)/Fe~(2+)in the electrolyte is 0.35. Decreasing the molar ratio of Zn~(2+)/Fe~(2+), the sample(S-1) is composed of ZnFe_2O_4 and α-Fe_2O_3, whereas increasing the molar ratio of Zn~(2+)/Fe~(2+), the sample(S-3) is composed of ZnFe_2O_4 and Zn O. The lattice parameters of ZnFe_2O_4 are influenced by the molar ratio of Zn~(2+)/Fe: Zn at excess decreases the cell volume whereas Fe at excess increases the cell volume of Zn Fe_2O_4. All the samples have the dendritic structure, of which S-2 has micron-sized lush branches with nano-sized leaves. UV–Vis diffuse reflectance spectra were acquired by a spectrophotometer. The absorption edges gradually blue shift with the increase of the molar ratio of Zn~(2+)/Fe~(2+). Photocatalytic activities for water splitting were investigated under Xe light irradiation in an aqueous olution containing 0.1 mol·L~(-1)Na_2S/0.02 mol·L~(-1)Na_2SO_3 in a glass reactor. The relatively highest photocatalytic activity with 1.41 μmol·h-1· 0.02 g~(-1)was achieved by pure ZnFe_2O_4sample(S-2). The photocatalytic activity of the mixture phase of Zn Fe_2O_4 and α-Fe_2O_3(S-1) is better than ZnF e_2O_4 and ZnO(S-3). Hierarchical dendritic micro-nano structure Zn Fe 2 O 4 have been prepared by electrochemical reduction and thermal oxidation method in this work. X-ray diffractometry, Raman spectra and field-emission scanning electron microscopy were used to characterize the crystal structure, size and morphology. The results The results show that the sample (S-2) is composed of pure ZnFe2O4 when the molar ratio of Zn2 + / Fe2 + is 0.35. Decreasing the molar ratio of Zn2 + Fe 2+, the sample S-1 is composed of ZnFe 2 O 4 and α-Fe 2 O 3, increasing increasing the molar ratio of Zn 2+ / Fe 2+, the sample (S-3) is composed of ZnFe_2O_4 and Zn O. The lattice parameters of ZnFe_2O_4 are influenced by the molar ratio of Zn ~ (2 +) / Fe: Zn at a decrease of the cell volume, Fe at excess increases the cell volume of Zn Fe_2O_4. All the samples have the dendritic structure, of which S-2 has micron-sized lush branches with nano-sized leaves. UV-Vis diffuse reflectance spectra were acquired by The absorption edges gradually blue shift with the increase of the molar ratio of Zn ~ (2 +) / Fe ~ (2+). Photocatalytic activities for water splitting were investigated under Xe light irradiation in an aqueous solution containing 0.1 mol · L -1 N 2 S / 0.02 mol·L -1 Na_2SO_3 in a glass reactor. The relatively highest photocatalytic activity with 1.41 μmol · h -1 · 0.02 g -1 was achieved by pure ZnFe 2 O 4sample (S -2). The photocatalytic activity of the mixture phase of Zn Fe 2 O 4 and α-Fe 2 O 3 (S-1) is better than ZnF e 2 O 4 and ZnO (S-3).