Over 70% of the Earth’s surface is covered by oceans, and the majority of the world’s population resides in coastal areas. Therefore, changes in sea level significantly impact the stable development of human society. Ocean altimetry helps us effectively grasp information about global sea level changes, polar sea ice melting, thermal expansion of seawater, and changes in the atmospheric ocean circulation system. These changes could potentially trigger extreme weather events, such as hurricanes and tsunamis, posing threats and obstacles to normal human life and socio-economic development. Major disasters, such as the tsunami in Indonesia and Hurricane Katrina, have resulted in significant casualties. Therefore, to predict and prevent ocean disasters in advance, it is necessary to establish a comprehensive early warning system, which requires data on global sea level changes and instantaneous sea conditions. In addition, the water resources of the ocean can affect the exchange of water vapor energy, thereby affecting atmospheric activities. Therefore, even minor changes in sea conditions can cause weather changes in some areas. To meet the needs of ocean and climate observations, it is essential to monitor sea level change.