Silver nanoparticles were synthesized from the extract of Fagopyri Dibotryis Rhizoma and the optimization of synthesis was studied. The absorbance of UV-visible spectroscopy was determined under the different influencing factors such as extracting time of Fagopyri Dibotryis Rhizoma powder, reation temperature of synthesis, volume of Fagopyri Dibotryis Rhizoma extract and concentration of AgNO3 to seek the optimization conditions. By means of FT-IR, TEM, DLS and XRD, the silver nanoparticles were characterized. The results showed that when the boiling time of Fagopyri Dibotryis Rhizoma powder was 5 min, resultant temperature was 25 degrees C, the volume ratio of 0.1 g x mL(-1) Fagopyri Dibotryis Rhizoma extract and 1 mmol x L(-1) AgNO3 was 1 to 10, and the reaction time was 3.5 h, the obtained silver nanoparticles had mean size about 27 nm and Zeta potential about -34.3 mV with good uniformity and dispersivity. Therefore, the green synthesis method of silver nanoparticles using extract of traditional Chinese medicine is stable and feasible.