Abstract: Abstract: People are more and more interested in health foods with the improvement of living standard. Edible lily tastes sweet with a little bitter and can be used to treat cough, phthisis, beriberi, and so on. There are almost 10 species of edible lily in China. The production of lily is in rapid expansion. However, the sample of lily is usually found to have cadmium (Cd) above the national standard. Cd is one of the toxic heavy metals. It will cause damage of lung and kidney. There are a lot of methods to detect the cd in foods, such as graphite furnace atomic absorption spectrometry, atomic fluorescence spectrometry, and spectrophotometry. Although these methods have high precision, they need large-scale equipment, high cost, and professional staff, and even some use toxic reagents. Scientists developed several rapid determination methods, one of which was electrochemical detection. In this paper, we designed a novel electrode, which combined screen printing technique with carbon nanodots to detect cd in lily. Carbon nanodots were prepared with candle soot which was low-cost and easily obtained. The carbon nanodots of 1.5 μL dissolving in dimethyl formamide were added twice onto the working electrode of screen-printed electrode which was fabricated in our laboratory. Using scanning electron microscope to compare the surface texture of modified screen-printed electrode with original one, we found that the former had more uniform particles. We also compared the electrochemical performance by cyclic voltammetry. The result showed that the modified screen-printed electrode had larger peak current and smaller peak separation which meant superior electrochemical performance. Furthermore, we tested an HAc-NaAc buffer solution with 75 μg/L Cd2+ using 2 different electrodes noted above by square-wave anodic stripping voltammetry. The peak potential of original screen-printed electrode was ?0.65 V, while modified one was ?0.64 V. The anodic stripping voltammogarm showed that the carbon nanodots modified electrode had larger response current and peak height. So we used the screen-printed electrode modified with carbon nanodots to detect a series of HAc-NaAc buffer solutions with different Cd2+ concentrations (30, 45, 60, 75 and 90 μg/L). The peak potential of very curve was -0.64 V. We found that peak height enlarged with the Cd2+ concentration increasing. A regression equation of peak height and Cd2+ concentration was obtained by calculating the data above. And the limit of detection was 0.91 μg/L according to the triple standard error principle. Get 4-5 g fresh lily, and then pound it to paste. Transfer the lily paste into conical flask. And digest the lily sample with 15 mL HNO3 and 5 mL H2O2 on the heating plate till moisture went. Finally, add 20 mL HAc-NaAc buffer solution to dissolve the residue, and then filter to get the solution for detection. The peak height of lily sample was used to calculate the Cd2+ concentration by the regression equation. The Cd2+ content of lily sample was 0.130 mg/kg, while the relative standard deviation was 1.1%. The Cd2+ content of lily was smaller than the China national standard NY 861-2004 and WM/T 2-2004. We also measured the recovery of standard addition of lily sample, which was 99.2%, 99.8% and 100.8%, respectively. It demonstrates that the modified electrode can be used to detect the cd content of lily. Because the carbon nanodots modified screen-printed electrode is low-cost, disposable, and easy to be produced, it will have a great prospect of application.