AgI-BiYO3 composite was synthesized by ultrasound-assisted precipitation process and characterized by using X-ray diffractometry (XRD), Fourier-transformed infrared spectroscopy (FT-IR), UV-visible diffused reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The photocatalytic activity of AgI-BiYO3 composite was evaluated from the photodegradation of Reactive orange16 (RO16) under ultraviolet (UV) and visible light irradiations. The sample designated as 16%AgI-BiYO3 showed superior activity relative to the other samples. The influence of reactive species on the degradation activity was investigated by using various scavengers and the results were discussed.