Yam is a kind of traditional Chinese medicine which contains many substances. It is of great significance to ensure the safe use of yam. In this article, the Raman peaks of the three pesticides, i.e., fenthion, triazophos, and thiram, were calculated by Gaussview/Gaussian09w. By combining with the surface-enhanced Raman spectroscopy (SERS) of the standard pesticide solutions, the Raman characteristic peaks of these three pesticides are determined. The pesticide residues of fenthion, triazophos, and thiram in yam were studied by using the self-assembled confocal Raman microscope as the detection device, and the gold nanosol was used as the enhanced substrate of SERS. The volume ratio of pesticides, hydrochloric acid, and gold sol particles was optimized experimentally. The experimental results show that the Raman peak bands of fenthion pesticide are around 717, 1050, and 1221 cm^-1, the lowest detection limit is 1 mg?L^-1, and the linearity R between the intensity of Raman peak and fenthion pesticide concentration is 0.9762 within the fenthion concentration range of 5?15 mg?L^-1. The Raman peak bands of triazophos are around 611, 978, 1001, 1321, 1408, and 1597 cm^-1, the minimum detection limit is 1 mg?L^-1, and the linearity is 0.9087 within the concentration range of 5?9 mg?L^-1.The Raman peak bands of thiram are around 556, 865, 1146, and 1506 cm^-1, the minimum detection limit is 0.1 mg?L^-1, and the linearity is 0.9905 within the concentration of 0?20 mg?L^-1. It is expected that the rapid on-site detection of pesticide residues in traditional Chinese medicines can be realized by using gold as the enhanced substrate for SERS.