In this work, a novel Bi2WO6-Fe2WO6 heterojunction (BWFO-10) was designed and fabricated by a facile hydrothermal process for the first time, in which rational synthesis of single-phase BiFeWOx and phase separated Bi2WO6-Fe2WO6 heterojunction was achieved by adjusting the pH value. More importantly, the 3D flower-like BWFO-10 superstructures was successfully synthesized at pH 10, which overcame the challenge of developing methods to synthesize Bi2WO6 superstructures under strong alkaline condition. Compared with pure BiFeWOx (62%), FWO (47%) and BWO (51%), the as-synthesized BWFO-10 composites exhibited a superior photocatalytic oxidation NO (similar to 400 ppm) activity (91%) under visible light (lambda > 400 nm) irradiation, which was ascribed to the effective separation of the photoinduced charge carriers, evinced by transient photocurrent and EIS measurements. The radical trapping experiment revealed that the h(+) and center dot OH were the important active species. And the test of stability revealed that the BWFO-10 composite could act as a desired photocatalyst for the oxidation of NO generated from fossil fuel combustion. A possible mechanism of the PCO of NO over BWFO-10 composites and the different evolution of crystal structures, growth and phase-change process had been concisely discussed. The study filled the gap of the currently reported synthesis method that 3D flower-like Bi2WO6 superstructure is not synthesized in alkaline conditions.