Abstract It is important to detect light of low power density sensitively and fast for the application of optical communication, environmental monitoring, astronomy, and national securities. However, ZnO‐based photodetectors exhibit long decay time owing to the persistent photoconductivity (PPC) and are hard to detect light with low power density efficiently. Here, a practical strategy is utilized to improve the performance of ZnO‐based photodetectors by coupling the pyroelectric effect of ZnO with localized surface plasmon resonance (LSPR) of Au nanoparticles subtly. Hence, a self‐powered photodetector is demonstrated, which is integrated with ZnO/CuO core–shell nanorods and Au nanoparticles to detect UV to vis light. This self‐powered photodetector achieves fast and sensitive detection of UV when power density is 68 nW cm −2 . The performance is significantly improved than the photodetectors without Au nanoparticles. The optimal responsivity and detectivity under the same power density of UV at 325 nm are 1.4 × 10 −4 A W −1 and 3.3 × 10 11 Jones. Response/recovery time is remarkably shortened to ≈10 ms. The results indicate that the material configurations and design concept make the device applicable for self‐powered, high‐performance photodetectors, and provide further promoted understanding of LSPR enhanced performance of photodetectors.