Gold nanoparticles (AuNPs) are used as fundamental materials in chemical/biological sensor applications, such as the DNA-AuNPs complex system for colorimetric sensor. As a result, the immobilization of AuNPs on target substrates is an important issue. In this study, we investigated the deposition of AuNPs on an amine-derivatized silicon wafer by in-situ AFM. Liquid-AFM allows structural changes and reaction kinetics of biomaterials and organic/inorganic nanomaterials in liquid media to be analyzed in-situ. The results showed that AuNPs were immobilized on an aminefunctionalized silicon wafer within a period of 1.5 hr.