BiOCl possesses special internal electrostatic field and is perpendicular to the (Bi₂O₂)²⁺ layer, which makes it tend to form nanoplatelets. It is well-known, the morphology and band gap of nanomaterials have a decisive effect on its photocatalytic performance. In this paper, a solid-phase chemical reaction was firstly used to prepare Bi_xO_yCl_z porous nanorods with different stoichiometric ratios by adjusting the ratio of reactants. The influence of the change in stoichiometric ratio on the microscopic morphology, energy band structure and photocatalytic performance of bismuth oxychloride was studied. Due to the rich pore structure that could increase the catalytic active sites and the appropriate energy band structure that could improve the absorption capacity of visible light, Bi₁₂O₁₇Cl₂ nanorods displayed the best photocatalytic performance under visible light, which can completely degrading rhodamine B and bisphenol A within 60 minutes.