Abstract: To achieve visual and rapid quantitative detection of chlorpyrifos in agricultural products, specific aptamers for chlorpyrifos were selected, and the interaction between the aptamers and chlorpyrifos was verified using molecular simulation. Leveraging the property of gold nanoparticles to aggregate and change color in high-salt environments and the protective effect of aptamers against the aggregation of gold nanoparticles, a colorimetric detection method using gold nanoparticles was established by optimizing the reaction system. Under the optimal conditions of 200 mmol/L NaCl concentration and 5000 nmol/L aptamer concentration, the method exhibited a good linear relationship within the chlorpyrifos concentration range of 10~1000 ng/mL (R²=0.997) and achieved a detection limit of 9.41 ng/mL. The recoveries of chlorpyrifos in fortified spinach and celery samples were 94.9%~102.8% and 97.2%~102.5%, respectively. Compared with the results obtained using the national standard method (GB 23200.121-2021), the developed method demonstrated good accuracy. This study provides a sensitive, specific, and accurate method for visual rapid quantitative detection of chlorpyrifos, which can enhance field detection efficiency and holds reference value for the study of aptamer colorimetric detection methods for organophosphate pesticide residues.