Granular lost circulation material (LCM) is the most commonly used material to reduce drilling fluid loss in drilling industry. Although, the plugging role of granular LCM in fracture is widely accepted by drilling engineers, the control and optimization are still limited due to the lack of the fundamental understanding of the LCM plugging process. This article presents a numerical study of the granular LCM plugging behavior at a particle scale by means of discrete element method (DEM). The effects of the particle shape, size distribution, and concentration on the fracture-plugging performance are studied by a series of controlled numerical experiments. The results are analyzed in terms of plugging depth and time spent before plugging. They are useful to the development of a better understanding and the control of granular LCM plugging process in fractures.