The BiOCl thin film with flower-like sphere structure was prepared at a low temperature by the alcoholysis-coating method using BiCl 3 as precursor. The obtained thin film was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), electronic energy spectrum (EDS) and ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS). And the results showed that the obtained BiOCl film without calcination was composed of flower-like sphere structure with tetragonal phase and had a good absorption for ultraviolet. The photocatalytic activity of BiOCl thin film was also evaluated by the degradation of methyl orange in water under UV light irradiation. The degradation experimental results confirmed that the film prepared at low temperature possessed a high photocatalytic activity and could achieve 97% degradation to 10 mg/L methyl orange solution after 150 min UV light irradiation. The stability of the obtained BiOCl thin film was also good and its photocatalytic activity still remained an above 94% removal of methyl orange after being used four times. In addition, a possible formation mechanism of BiOCl thin film was also inferred and the results suggested that the ethylene glycol solvent may contribute to the forming flower-like sphere structure. The BiOCl thin film with flower-like sphere structure was prepared at a low temperature by the alcoholysis-coating method using BiCl 3 as precursor. The obtained thin film was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) electronic energy spectrum (EDS) and ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS). And the results showed that the obtained BiOCl film without calcination was composed of flower-like sphere structure with tetragonal phase and had a good absorption for ultraviolet. The degradation experimental results confirmed that the film prepared at low temperature possessed a high photocatalytic activity and could achieve 97% degradation to 10 mg / L methyl orange solution after 150 min UV light irradiation. The stability of the obtained BiOCl thin film was also good and its photocatalytic acti vity still remained above an 94% removal of methyl orange after being used four times. In addition, a possible formation mechanism of BiOCl thin film was also inferred and the results suggested that the ethylene glycol solvent may contribute to the forming flower-like sphere structure .