Nowadays, the use of chemical fertilizers, plant protection chemicals, pesticides, and herbicides and the wastes of manufactories, industrials zones have caused the pollution of soil, water, and air. Thus, vegetables may be contaminated by some heavy metals such as As, Hg, Sn, Cd, Cu, Zn..., which produce toxic substances and harmful bacteria. Hence, the authors select the research: "Determining the content of Cadimi in vegetables in Dai Tu (Thai Nguyen province) by atomic absorption spectrometry method (F-AAS)". According to the results the contents of Cadimi on the ten samples of vegetable are lower than Vietnam standard (TCVN46/2007).