In this paper, silver nanoparticle substrate was prepared by hydrophobic concentration effect based on super hydrophobicity of the leaf of Tradescantia pallida. The tradescantia-pallida-leaves substrate can enhance Raman signal well for the rhodamine 6G (R6G). the detection limit for R6G could reach 5×10^-11mol/L, indicating that it had a good enhancement effect. In addition, comparative analysis was conducted on the SERS spectra of the substrate of front side and the back side of tradescantia-Pallida leaves, and it was found that there was little difference in the enhancement effect. So the front side was selected for the substrate to next experiment. The prepared substrate was used for the detection of Thiram residue, and the detection limit also reached 5×10^-8mol/L. The detecting concentration well lower than the Latest national standard of maximum residue limit of 0.1mg/kg (about 4.16×10^-7mol/L). The SERS substrates could be used for fast detection of Thiram residue. Furthermore the substrate is very easy to prepare and can be prospectively used as a rapid method for the detection of pesticide residues.