Aiming at the shortcomings of high cost and time-consumption in traditional liquid chromatography, an effective surface enhanced Raman scattering (SERS)-based trace detection method has been proposed to quantitatively identify the active component of traditional Chinese medicine. In this paper, a high-performance and versatile SERS platform based on Ag nanoparticles (NPs) self-assembly Ag-anodized aluminium (Ag NPs-Ag-AAO) nanoarray was fabricated by controllable physico-chemical preparation technology. The results indicated that the electromagnetic field enhancement effect was sharply strengthened as Ag NPs assembled, and the experimental enhancement factor (EEF) value was calculated to be 1.0083 × 10⁶. This novel Ag NPs-Ag-AAO nanoarray with substantial “hot spots” exhibited high SERS signal reproducibility, with the relative standard deviation (RSD) value at less than 2.23%. More importantly, this SERS platform was applied to detect active component Baicalein in Scutellaria baicalensis, and the limit of detection (LOD) was located at 10 fg/mL. Therefore, this Ag NPs-Ag-AAO nanoarray with high sensitivity, strong Raman signal reproducibility and reliable practicability has broad application prospects in the rapid detection of trace substances in the active components of traditional Chinese medicine and is expected to be popularized.