Abstract: Ineffectively utilized pesticides can have an impact on food safety through environmental and dietary exposure. This can lead to the formation of trace residues in the human body, which can potentially harm human health. Detecting and analyzing these trace pesticide residues in human samples is challenging due to the complex matrix and low levels of pesticides. Traditional sample pretreatment methods like liquid-liquid extraction and solid-phase extraction are not suitable for this purpose. To address this issue, targeted nano-adsorbents, such as functional Fe₃O₄ nanoparticles, have been developed. This article introduces the technical advancements of functional Fe₃O₄ nanoparticles, which have efficient separation characteristics and are used for trace pesticide residue analysis. The article reviews the synthesis methods for the magnetic core of these nanoparticles (chemical co-precipitation, thermal decomposition, solvothermal reaction, etc.), different types of group modifications (natural polymers, carbon-based materials, metal-organic framework materials, inorganic materials, etc.), application matrices (environmental water, fruits, vegetables, and biological samples), as well as the types of pesticides and analysis efficiency. The principles of targeted preparation, application characteristics, and the latest research progress of these nanoparticles were highlighted. The current challenges that need to be addressed and the future prospects for using functional Fe₃O₄ nanoparticles in the analysis of trace pesticides are also discussed. It provides a theoretical reference for the extended application of new nano-adsorption methods.