Freestanding nanoparticle membranes over circular wells are prepared by utilizing surface engineering. The crucial step of this method is the hydrophobic treatment of the substrate surface, which causes the water droplet to be suspended over wells during drying. Consequently, the nanopartide monolayer self-assembled at the surface of the water droplet would drape itself over wells instead of being dragged into wells and ruptured into patches after the evaporation of water. This scenario was confirmed by the results of control experiments with change & in the hydrophobicity of the surface and the depth of wells. Moreover, the NaCl crystallization experiment provide additional evidence for the dynamic process of drying. Freestanding nanopartide membranes with different nanopartide core sizes and different lengths of ligands have been successfully prepared using the same rOute The Young's modulus of one typiCal kind of prepared freestanding nanoparticle membrane was measured with force microscopy.