Recently, layer-by-layer sequential adsorption technique is applied to many devices. We reported that the thickness and the surface structure of the layer-by-layer sequential adsorption film using Poly (allylamine hydrochloride) (PAH) and Poly (acrylic acid) (PAA) were systematically controlled with mn scale order by changing pH of polyelectrolytes solution. In this study, we present the first observation results on the initial adsorption processes of polyelectrolytes to the substrate in solution by in-situ observation using an AFM. It was found that the surface structure was strongly effected by the previously formed under layer and the solution pH.