In order to obtain a ZnO-based broadband photodetector with a multi-band response， ZnO is coupled with other narrow-bandgap semiconductors to construct the heterojunction. In this study， ZnO nanorods （NRs） arrays were first grown on FTO substrates through the hydrothermal process. Then， Bi₂S₃ quantum dots （QDs） were synthesized on the surface of ZnO NRs via the successive ionic layer absorption reaction method， thereby successfully constructing the ZnO NRs/Bi₂S₃ QDs heterojunction. The micro-morphology and elemental composition of as-prepared samples were characterized using a scanning electron microscope and energy dispersive spectrometer. The results show that the Bi₂S₃ QDs are uniformly and densely attached to the surface of ZnO NRs that are slightly curved and partially intertwined at the top. Then， a broadband photodetector was fabricated based on the as-prepared heterojunction. In addition， the photodetector based on the ZnO NRs/Bi₂S₃ QDs heterojunction can operate without an external power source， indicating that the photodetector has a self-powered feature. Compared with the ZnO NRs photodetector， the maximum photocurrent of the ZnO NRs/Bi₂S₃ QDs photodetector under UV light irradiation increases by approximately 0.065 mA. This is mainly because the type II band alignment between ZnO and Bi₂S₃ increases the separation efficiency of photogenerated charge carriers. Furthermore， the ZnO NRs/Bi₂S₃ QDs photodetector has excellent detection capability for visible light， exhibiting excellent cycle stability when irradiated by blue （470 nm） and green light （530 nm）.