Abstract: Gold nanoparticles ( Aunps) have been investigated as novel marking materials for their unique luminescent properties.Aptamer is a type of recognition materials with specific binding ability to capture target molecules and have been widely applied in the field of analysis and detection. In our study, a novel detection method for quantitative analysis of sulfadimethoxine was developed based on Au NPs and aptamer.The proposed method was applied to the analysis of real samples.The recoveries were 85.64% and 89.86%, and the relative standard deviation ( RSD) values were 4.00%, 5.28%, and 5.88%, 6.67%, for intra-and inter-day tests, respectively.The linear range of the method was 1¹0 ng/m L, and the detection limit was1 ng/m L.The above results suggested that the proposed method was highly accurate, and precise, and was feasible for the quantification of target sulfadimethoxine in aquatic product.