The work aims to investigate the effects of different reducing agents on the particle size, size distribution and morphology of nano-silver particles during their synthesis. With polyvinylpyrrolidone (PVP) as dispersant, and glucose, ascorbic acid, sodium citrate and ethylene glycol as control, the nano-silver particles were prepared by chemical reduction method and the reaction temperature was controlled at 60 ℃. The prepared silver particles were characterized by Malvern particle size analyzer, X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM), and ultraviolet-visible spectroscopy (UV-vis), etc. Spherical nano-silver with smaller particle size (average particle size: 51 nm) and uniform distribution was obtained, when glucose was used as reducing agent. When ascorbic acid was used as reducing agent, spherical aggregates formed by aggregation of crystal particles appeared, with an average particle size of 67 nm. Nano-silver particles reduced by sodium citrate were concentrated at about 15 nm and about 100 nm with an average size of 57 nm. Under the same conditions, the ethylene glycol reduced nano-silver particles of spherical, rod and triangular plate shapes, with an average size of 107 nm. With glucose as reducing agent, it is easier to prepare spherical nano-silver particles with small particle size and uniform dispersion.