It is common with a macro-scale approach to investigate the particulate solids flow properties; it is also sometimes necessary and crucial in such efforts with a micro-scale approach. In the present proposal, the discrete element method (a micro-scale approach) was adopted to model the particulate solid flow pattern during discharging from a two-dimensional plane silo, and the effect of flow-aid device (a cone-in-cone insert) on such process. In the model, the effects of liquid bridge on the flow property were also considered. It is found that a presence of a cone-in-cone insert could improve the flow pattern of silo discharging, from a funnel flow to mass flow by its optimal location. Meanwhile, the effects of such an insert on the loads on the wall of silos were also investigated. The influences of properties change caused by the liquid bridge between particulates upon the flow patterns and the discharging rate of particulate solids from silos were also addressed.