Abstarct: Aflatoxins are toxins on food they are known as the leading mycotoxins due to their considerable abundance in the environment and the possibility of their growth in many agricultural products and their toxic and carcinogenic properties they are known as the mainstay of mycotoxins. Nanotechnology has made significant strides in identifying pathogens. The use of nanoparticles as markers in joints and with new detection methods has led to improvements in the detection sensitivity and microbial detection capacities. Therefore, this experiment was performed with the aim of designing an electrochemical biosensor baxsed on gold nanoparticles to detect aflatoxin B1. In this experiment, carbon electrodes were first washed and then added with gold nanoparticles and in the next step, the aptamer was placed on the electrode, after which the selectivity and stability of the electrode were evaluated. The results of this experiment showed that in the presence of aflatoxin, a specific aptamer, aflatoxin B1, was attached to it and it was stated that a well-designed biosensor was able to detect aflatoxin. And increase the sensitivity of this biosensor by using gold nanoparticles, So that the results of this experiment in the first place showed the coordinated distribution of gold particles on the surface of the electrode and the cyclic voltmeter showed good detection of aflatoxin by the electrode. Also, according to the results of this test, the stability of the modified electrode was optimal and acceptable up to 22 days. Finally, the results of this study show that the designed electrode has good selectivity and optimal repeatability.