BiOI/BiOBr heterojunction composite catalytic material was synthesized with solvothermal method. Its degradation ability of rhodamine B was investigated. The photocatalytic performance of the BiOI/BiOBr heterojunction,BiOBr and BiOI was compared. The structure,morphology and optical properties of the samples were characterized by X- ray diffraction (XRD),field emission scanning electron microscopy (FESEM),UV-vis diffuse reflection spectrum (UV-vis DRS),steady-state and transient-state PL spectra. The degradation rate of rhodamine B was analyzed by spectrophotometry. The results showed that the BiOI/BiOBr heterojunction photocatalytic materials had good degradation ability to 100 mg/L rhodamine B,indicating that the degradation rate of rhodamine B was 100% in forty minutes,significantly higher than that of pure BiOBr (80%) and BiOI (72%). The first order kinetic rate constant was 0.102 8 min-1,2.6 times of BiOBr (0.040 3 min-1) and 3 times of BiOI (0.034 4 min-1),respectively. This heterojunction photocatalyst can both effectively promote the photogenerated charge separation and maintain the strong redox ability of the composites,which may be the internal reason for efficient degradation of Rhodamine B by BiOI/BiOBr heterostructures.