The objective of this research was to develop a rapid detection method based on nanoparticles to quantify the aflatoxin B1 (AFB1) in oilseeds. Liquid-solid extraction (LSE) combined with immune magnetic solid-phase extraction (IMSPE) via nanoparticles was developed for the determination of AFB1 in oilseeds. Self‐synthesized antibody functionalized magnetic nanoparticles (MNPs) were firstly synthesized and characterized using FT‐IR and TEM before being used to extract the AFB1 in oilseeds. Due to the highly selective extraction with the aid of antibody-antigen interaction, the MNPs captured the AFB1 in the samples highly efficiently. After the extraction process, the AFB1 was detected and quantified using HPLC-Fluorescence Detection. The extraction method was optimized based on several crucial factors which affect its efficiency, namely, the low temperature clean-up duration, the volume of MNPs used in IMSPE and the vortex duration for IMSPE. Based on the results obtained, the optimum conditions were 20 h, 1 mL and 5 min, respectively. Subsequently, a calibration curve constructed with spiked samples of known concentrations yielded a correlation coefficient of 0.9946, showing strong linearity over a concentration range of 0.1-100 ng·g-1. The limits of detection and quantification of the method were estimated to be 0.02 and 0.05 ng·g-1, respectively. The proposed method also showed satisfactory repeatability, with intra and inter-day method recovery rates ranging from 94.92-118.95%. Lastly, real sample analysis was carried out on five oilseed samples. The proposed method was highly accurate, sensitive and reliable. The results show the promising in detecting AFB1 contamination in oilseeds rapidly.