Monodispersed silver nanoparticles (Ag NPs) in controllable size were prepared by solution chemical reduction with glucose as the reducing agent and chitosan as the stabilizing agent. The effects of the concentration of reducing agent, stabilizing agent and silver nitrate, temperature, pH value and reaction time etc. on the nucleation and subsequent development of Ag NPs were evaluated by means of ultraviolet-visible spectrophotometry, X-ray diffraction and transmission electron microscopy. Monodispersed silver nanoparticles with diameter of 3? nm、6? nm and 9? nm were obtained respectively as a result.