Abstract: Inorganic ions in plants can be determined by using the near-infrared spectral(NIRS)technique,because they combine with the organic groups that have NIRS absorptions.The present study explored the feasability of applying near-infrared diffuse reflectance spectrometry for rapid determination of Cu,Zn and Cd contents in sweet potato leaves and stems.Sixty-seven leaf and same number of stem samples were collected from sweet potato plants grown under different fertilizations.The partial least square method was used for calibrating spectral data with their corrsponding water,protein,Cd,Cu and Zn contents of the sweet potatoes.The results showed that the established models could rapidly predict the contents of Cu,Cd and Zn in the leaves and stems.However,the model needed to be refined further for accurate applications.