A chitosan (CTN)/silica-supported nanosized palladium catalyst was obtained from a silica-supported chitosan palladium complex through a complex transition method. An adsorption model was employed to simplify the structure of the di-supporter. It was indicated that when the polymer coil adsorbed on the silica surface with even a monolayer the catalytic activity would reach an optimum value, and different situations of the, nanosized palladium particles would cause a different catalysis. The molar ratio of the chitosan structure unit to the palladium would affect the metal's size, which therefore influenced its catalytic activity. The experimental results corresponded with the inferences.