In this work firstly BaFe12O19 nanoparticles were synthesized via a fast and facile chemical procedure at solvent of water. Then BaFe12O19–ZnO nanocomposites were synthesized by a sono-chemical method. The effect of temperature, solvent, precipitation agent and various surfactants on the morphology and size of the products was investigated. The prepared products were characterized by X-ray diffraction pattern, scanning electron microscopy and Fourier transform infrared spectroscopy. Alternating gradient force magnetometer illustrated either super-paramagnetic or ferromagnetic behaviour of BaFe12O19 nanostructures. The photocatalytic behaviour of BaFe12- O19–ZnO nanocomposites was evaluated using the degradation of acid blue, acid brown, acid black and congored under ultraviolet light irradiation. The results show that nanocomposites have applicable magnetic and photocatalytic performance.