We investigate the capillary effects during droplet formation on pillar surface via a dewetting process. The microdroplet formed from the fluid remains on the top surface of micropillar after the dewetting process. The simulation results show that the ratio of the diameter of microdroplet (Dd) and the diameter of micropillar (Dp) is correlated as 3.26Re0.25 for H/Dp<0.5, where Re is the Reynolds numbers and H is the liquid thickness between the top surface of micropillar and the upper substrate. The analytical solution for growth droplet based on the conservation of energy is provided. The numerical results show that our prediction is consistent with the analytical solution for a large range of Re number.