The Macau Airport’s reclamation project has narrowed the connecting waterway that connects Ka-Ho Bay and Macau Waterway，and the hydrodynamic environment around the project has also changed accordingly. We establish a numerical model of tidal current dynamics in the sea area near Macau，simulate the tidal current changes in Ka-Ho Bay before and after the Macau Airport reclamation project based on the CJK3D model，and discuss the response mechanism of tidal dynamics and water exchange capacity in Ka-Ho Bay to reclamation from the aspects of tidal characteristics and water exchange cycle.The results show that：1）The reclamation project of Macau Airport will not cause the overall flow pattern of Macau waters to change，but its narrowing effect will cause Ka-Ho Bay to approach a semi-enclosed bay. 2）The flux of ebb and flow tides in the section of bay mouth has decreased significantly，and the tidal current velocity decreases. The half exchange period increases，and the tidal power and water exchange capacity are weakened.