Objective: This study focused on the preparation of a new electrochemical sensor for detection of heavy metal content in food. Methods: In this study, a new type of bismuth-based metal-organic framework was prepared by hydrothermal method. 1,3,5-benzenetricarboxylic acid （H₃BTC） was used as a ligand, which supplemented by bismuth nitrate pentahydrate [Bi（NO₃）₃ 5H₂O] and cobalt nitrate hexahydrate [Co（NO₃）₂·6H₂O] metal salts to prepare novel bismuth-based metal-organic frameworks. Bi-based metal-organic framework composites supported by multi-walled carbon nanotubes were prepared by ultrasonic self-assembly. The surface of glassy carbon electrode （GCE） was modified by dropping casting. Results: The Bi-Co-BTC/MWCNTs/GCE was used as the working electrode to realize the simultaneous detection of Zn²⁺, Cd²⁺, and Pb²⁺ in the sample, and the detection limits were 0.040 3, 0.005 69, 0.023 9 ng/mL respectively. The recovery of Zn²⁺,Cd²⁺and Pb²⁺ in the tea were 97.21%～105.44%, 92.22%～106.10% and 93.97%～98.02%, respectively. Conclusion: The results show that Bi-MOF/MWCNTs/GCE can be used to detect the content of heavy metals in food.