From the perspective of social network, this paper took the opinion leader, spiral of silence and group polarization integrally in a simulation model. The study found that the size of the group had positive impact on the discussion time cycle, the number of active speakers, and the number of nonactive speakers; personal character had positive impact on the discussion time cycle, but the marginal benefts diminished; the proportion of core fgures could reduce the gap on both discussion time cycle and amount between the active and non-active speakers; the combination of personal character and proportion of core fgures would signifcantly cause group polarization; the in?uence of core fgures on the discussion time cycle and amount would be more significant while the network structure changed; in a scale-free network, the reversal of the discussion time cycle and amount was in?uenced by the combination of proportion of active speakers and proportion of core fgures.