Remarkable global cooling happened since the Pliocene about 3~4Ma ago. This cooling was often linked to changes in seaways during this period. Previous modelling studies focused mainly on the changes in tropical seaways, including the closing of Central America Seaway and the narrowing of Indonesian Seaway, but paid less attentions to changes in high latitude seaways, for example the opening of the Bering Strait. With the Norwegian Earth System model, this study simulates the climate effects due to the changes in the tropical seaways and the Bering Strait. These simulations demonstrate that the changes in the tropical seaways and the Bering Strait cause surface climate responses in most global regions. The opening of the Bering Strait causes the climate responses mainly in mid- and high-latitudes. The closing/narrowing of the tropical seaways leads to cooling in most regions, but warming in the tropical Pacific. Regionally, the closing/narrowing of the tropical seaways plays a more important role in Chinese climate evolution during the Pliocene, in relative to the opening of the Bering Strait. The closing/narrowing of the tropical seaways causes climate responses in Northeast and Southwest China. In Northeast China, the annual temperature decreases about 0.2~0.6℃,and the annual precipitation decreases by 100mm. In Southwest China, the annual temperature increases about 0.2-0.6℃, and the annual precipitation decreases more than 100mm. In contrast, the climate responses due to the opening of the Bering Strait are insignificant in China. The importance of tropical seaways on the regional climate in China is linked to the modification of tropical ocean temperature. The closing/narrowing of the tropical seaways, which intensifies the temperature gradient between the east and the west tropical Pacific and enhances ENSO variability,leads to the stronger regional climate responses in China, in relative to the opening of Bering Strait.