Recyclable surface-enhanced Raman scattering (SERS) substrates integrating high sensitivity with effective photocatalytic self-cleaning capability are highly desirable for sustainable pollutant analysis, yet maintaining stable SERS activity during repeated photocatalytic regeneration remains challenging. Herein, a photocatalytic self-cleaning AuNBPs@TiO₂ SERS chip was constructed by integrating plasmonic gold nanobipyramids with a photocatalytic TiO₂ shell. By regulating the hydrolytic coating process, a uniform TiO₂ shell with an optimized thickness of approximately 10 nm was obtained, providing a balance between SERS enhancement and photocatalytic activity. Using methylene blue (MB) as a model organic pollutant, the chip exhibited a wide linear detection range from 10 nM to 1 mM with a low limit of detection of 3.3 nM. The intra-chip and inter-batch relative standard deviations were below 10%, indicating good uniformity and reproducibility. Furthermore, time-dependent SERS spectra enabled in situ monitoring of MB photodegradation under xenon lamp irradiation, with degradation efficiencies exceeding 95% within 90 min for MB concentrations of 10^⁻4−10^⁻6 M. Independent UV-vis measurements further confirmed MB degradation, showing an 81.91% decrease after 90 min for 10^⁻5 M MB. After 12 cycles, the chip retained approximately 72% of its initial SERS signal while maintaining a degradation efficiency above 90%. The AuNBPs@TiO₂ chip offers a reusable SERS platform for sensitive MB detection and in situ monitoring of photocatalytic degradation, demonstrating the feasibility of integrating trace detection, photocatalytic regeneration, and repeated use within a single analytical platform.