The tip-enhanced Raman spectroscopy (TERS) provides a non-destructive and label-free molecular detection approach with high sensitivity due to the hotspot excited at tip apex, which depends crucially on the tip parameters. Here, we employed an Au cladded atomic force microscopy probe to investigate enhancement effect of the Au claddings, both in theories and experiments. The simulation optimized a highest enhancement with Au cladding thickness of 50 nm under given experimental condition, being consistent with the experimental results. It provides a practical guide to optimize the probes to improve the TERS sensitivity and exert potentials in further TERS applications.