The work aims to investigate the effects of different reducing agents and other experiment additives on the particle size, size distribution and morphology of nano-silver particles during the chemical reduction synthesis. Silver nanoparticles were prepared by chemical reduction at room temperature with ascorbic acid as reducing agent, polyvinylpyrrolidone (PVP) as dispersant, sodium citrate as protective agent and second reducing agent, and glucose and sodium borohydride were selected as control. The prepared silver nanoparticles were characterized by Malvin laser particle sizer, UV-Vis and TEM. With ascorbic acid as reducing agent, spherical silver nanoparticles with small particle size (average particle size of 56 nm) and uniform size distribution were prepared by adjusting the volume of ascorbic acid (0.2 mL), fixing the volume of sodium citrate to 0.5 mL and PVP to 0.6 mL; however, the size of silver nanoparticles was too large (the average particle size was 216 nm and 189 nm, respectively) when glucose and sodium borohydride were used as reducing agents. With ascorbic acid as reducing agent and adjusting the experimental parameters such as sodium citrate and PVP in the optimal range, it is easier to prepare uniform nano-silver solution with good sphericity and small particle size.