The observation of a conduction two-dimensional electron gas (2DEG) in the LaAlO₃/SrTiO₃ (LAO/STO) heterostructure is a well-known example of interface physics with new paradigms. While most of the studies are aiming to broaden the scope of interfaces by combining different materials, play a crucial role to real device applications by controlling the interface through external stimuli. In this paper, we propose a generic approach to pump the foreign electrons into the 2DEG of the LAO/STO heterointerface by using Au(111) nanoparticles as an external stimuli on the LAO/STO interface. We have studied the conductivity of the LAO/STO interface as a function of LAO thicknesses, densities and sizes of Au nanoparticles. The conductivity of the LAO/STO interface can modulate with the control of LAO thickness and density (or size) of Au nanoparticles. When shining light on the enriched to the interface. More importantly, the interfacial conductivity between LAO(3u.c) and STO was really enhanced after depositing the Au nanoparticles on the layer of critical thickness (3u.c) of LAO but still shows the insulating behavior. However, we observed dramatic change in the interfacial conductivity when the visible light is illuminated on the sample. The interfacial conductivity switches from insulating to metallic state. This study suggests a new avenue of controlling the conduction of complex oxide interfaces.