The effect of pore drag on grain growth is one of the most frequent effects encountered in the last stage of sintering. Therefore, the understanding of the effect of microstructure and pore location, pore morphology on grain growth is essential. Here a migrating grain boundary interacts with pores and other grain boundaries such that its structure and energy vary during grain growth. Consequently, it is of great interest to see whether the grain boundary energy decreases or increases during the interaction between migrating grain boundaries and pores. In this paper, the conditions for grain boundary migration and pinning are related to pore curvature and illustrated theoretically and experimentally.