Taking glyphosate pesticide sold in the market as test sample and capillary glass tube with Ag nanoparticles adsorbed on the inner wall as active substrate, the surface enhanced Raman spectra (SERSs) of the glyphosate and its volatiles in the air are studied to explore a new method for determination of the pesticide residues using the pesticide volatiles. Using prepared Ag colloid substrates, the SERS detection is performed on commercially available glyphosate pesticides with different concentrations, and the detection concentration of the glyphosate can be as low as 1.8×10 ^-6 mol/L. Next the SERS of the volatiles of glyphosate solutions with different concentrations are studied by using the prepared capillary glass tube. When the glyphosate solution is diluted to a concentration of 1.8×10 ^-6 mol/L, there is still a significant characteristic absorption peak of the glyphosate, which indicates the detected concentration of the experimental method can reach 1.8×10 ^-6 mol/L (about 0.3 mg/kg). According to the National Food Safety Standard formulated in 2016, the maximum glyphosate residue in fruits is 0.5 mg/kg. Compared with the national standard,the concentration of the glyphosate pesticide residues in the detected water has basically reached the national maximum detection standard of pesticide residues. Therefore, this experimental method can be used as a scientific and effective method for the detection of glyphosate pesticide residues and can provide a reference for detecting other pesticide residues.