Objective To investigate the contamination levels of aflatoxin B1 (AFB₁) in fermented tea, including dark tea, black tea and oolong tea, and evaluate their health risk. Methods The sampling was determined by the simple random sampling method. A total of 260 tea samples(dark tea, black tea and oolong tea)were collected from supermarkets, wholesale markets, tea shop and online store in 9 prefecture-level cities of Guangdong Province. AFB1 concentrations were examined according to GB 5009.22-2016. By using the method of margin of exposure (MOE) and mathematical modeling, the AFB₁ dietary exposure in tea was assessed. Results The detection rate of AFB₁ in 260 fermented tea samples was 1.15% (3/260), and the detected content range was from 0.26 to 0.56 μg/kg. The three AFB₁ positive samples of were Pu'er tea samples. There was no significant difference in the detection rate between three kinds of fermented tea (Fisher exact probability method, P>0.05). The average dietary exposure of AFB₁ from tea of the total survey population and the tea consumption population were 0.000 352, and 0.000 981 ng/kg BW, respectively. The dietary exposure was 0.005 73,0.016 0 ng/kg BW for the total survey population and the tea consumption population when using the maximum value of AFB₁ in this study. On the basis of European Food Safety Authority (EFSA) criterion, the MOE values were both greater than 10 000, indicating that the health risk associated with AFB₁ in tea in Guangdong was relatively low. The evaluated liver cancer risk was 0.000 010 9-0.000 674 caners per one hundred thousand persons. Conclusion The detection rate and the content of AFB₁ in fermented tea in Guangdong Province were both low. And the health risk associated with AFB 1 in tea was relatively low, either.