Abstract: Aflatoxin B₁ (AFB₁) is the most common class of contaminants in natural foods, and it is also the most toxic and carcinogenic. In this work, metal organic framework nanoenzyme (Mn MOF) with catalase-like properties were synthesized. The Mn MOF-C was obtained after high-temperature carbonization, and the composite Pt NPs@Mn MOF-C was obtained by doped platinum nanoparticles, which was found that its catalytic capacity could be further enhanced. The composite was used as a marker to prepare the AFB₁ aptamer sensor. The aptamer with high affinity and high specificity can be specifically bind to AFB₁ and dissociates from the electrode surface, resulting in a reduced current signal catalyzed by Pt NPs@Mn MOF-C, thus achieving quantitative detection of AFB₁ in food. In the range of 0.001 to 100 ng/mL, the response signal gradually decreased as the mass concentration of the target AFB₁ increased. The aptasensor constructed in this work has high sensitivity and short time consuming, and can be used for AFB₁ detection in real rice samples, showing good application prospects.