<p>Peanuts, corn, and other crops are highly susceptible to the production of Extremely toxic and highly carcinogenic aflatoxins during both production and storage. The most common types include B1, B2, G1, and G2, among which aflatoxin B1 is the most toxic, exhibiting extreme hepatotoxicity, mutagenicity, and carcinogenicity. Long-term ingestion may lead to serious health issues such as liver cancer and immune suppression. Consequently, the development of a highly sensitive, quick, and non-invasive method for detecting aflatoxin B1 is imperative.This study investigates highly sensitive quantitative detection of aflatoxin B1 based on terahertz BIC metamaterial enhancement. A bound state in the continuum (BIC) metamaterial was designed based on electromagnetic theory and the finite-difference time-domain (FDTD) method, enabling ultrasensitive detection of aflatoxin B1 solutions.Terahertz enhanced spectra of aflatoxin B1 solutions at varying concentrations showed that the transmission peak amplitude near 1.5 THz decreased progressively with higher concentrations, and the peak frequency shifted toward lower frequencies in a concentration-dependent manner. Quantitative models for aflatoxin B1 detection were established using Partial Least Squares (PLS) and Least Squares Support Vector Machine (LS-SVM). Comparative analysis revealed that the LS-SVM model demonstrated superior performance, achieving a detection limit of 2.04 × 10^− 7 µg/mL for aflatoxin B1. This work provides preliminary validation for the feasibility of highly sensitive detection of aflatoxin B1 solutions using a BIC terahertz metamaterial sensor combined with THz-TDS technology. The research provides both theoretical foundation and a novel detection method, which will facilitate rapid, non-destructive, and highly sensitive detection of aflatoxin B1 in agricultural products.</p>