The Raman spectra of Dangshen medicinal materials are tested in different positions. The normal Raman spectrum and surface-enhanced Raman spectrum (SERS) of Dangshen decoction are tested and analyzed .The intensity of the SERS of Dangshen decoction in the silver colloid is increased obviously. The characteristic Raman bands of Dangshen decoction were tentatively assigned. The absorption spectroscopy of Dangshen decoction and the mixture of silver colloids and Dangshen decoction are measured. A new resonance absorption peak was observed in the long-wavelength region in UV-Vis absorption spectra of the mixture. The adsorption characteristics and possible enhancing mechanism of the Dangshen decoction on silver colloid were speculated. The results show that the surface-enhanced Raman spectroscopy might provide a new kind of precise,direct and fast detecting method for the detection of Dangshen decoction or other Traditional Chinese medicine.