Uniform BiOCl hierarchical microspheres assembled by nanosheets with tunable thickness were synthesized via a simple solvothermal route. XRD, SEM, TEM, XPS, BET, UV-vis and DRS were performed to investigate the structural and optical properties of the samples. The results indicated that the morphology and structure of the BiOCl could be controlled by adjusting the pH values. With the increase of the amount of ammonia solution, the thickness of assembled nanosheets became thinner from 50 nm to 10 nm or even less than 10 nm. The specific surface area of BiOCl hierarchical microspheres increased as well. The influence of different pH value on the performance of BiOCl hierarchical microsphere was studied systematically. All the BiOCl hierarchical microspheres showed higher photocatalytic activities for the RhB degradation than commercial P25 under visible light irradiation. The sample obtained at pH 5 showed the highest activity for dye photosensitization degradation of RhB under visible light irradiation due to the large specific surface area and considerable oxygen vacancies. Furthermore, the BiOCl hierarchical microspheres also exhibited high photocatalytic performance for the direct semiconductor photoexcitation degradation of salicylic acid and phenol under UV light irradiation. (C) 2015 Elsevier B.V. All rights reserved.