Objective: Aflatoxin B1 pollution is the key factor affecting food quality and safety. How to degrade aflatoxin B1 to reduce pollution and explore the degradation mechanism is the current urgent demand. Methods: Aflatoxin B1 in acetonitrile solution was degraded by plasma treatment with a discharge power of 200 W， a discharge time of 5 s and a discharge distance of 0.4 cm， and analysed by high performance liquid chromatography-mass spectrometry (HPLC-MS/MS) and high resolution mass spectrometry (HRMS) with the aim of obtaining the products and pathways for the degradation of aflatoxin B1 in the dielectric barrier discharge plasma method. Results: The molecular and structural formulae of five degradation products were analysed， and their degradation pathways were Criegee mechanism， Benzyl Methoxy Reaction and Nucleophilic Reaction. With the degradation rate of 35.8%， it was demonstrated that the toxicity was consistent with the degradation rate after dielectric barrier discharge plasma treatment based on the loss of toxicity sites of the five degradation products. Conclusion: This study provides a theoretical reference for the degradation of aflatoxin B1 in peanut， corn and nut products using dielectric barrier discharge plasma， and the potential toxicity validation after degradation of aflatoxin B1 by dielectric barrier discharge plasma can be further explored in subsequent experiments through animal experiments or cell experiments.