In multi-hop wireless sensor networks, the sensors closest to the sink tend to deplete their energy faster than other sensors, which is known as energy-hole problem. to balance energy dissipation, we first investigate the location of the static sink in terms of energy efficiency. we study the mobile sink model, and coclude the best mobility strategy. we than consider jointly sink mobility and hybrid communication, and propose a hybrid communication model based on taking both static sink and mobile sink into account. we finally conduct extensive experiments and find that the number of alive sensors can be increased significantly as compared to not only the static sink but also the mobile sink.