Abstract: A growing number of hydropower stations are being built overseas in recent years. As the owners of projects attempt to save investment and are often inadequately acquainted with hydropower stations, they usually tend to demand optimization of the diversion system and canceling surge chamber, or a reasonable explanation of the necessity of surge chamber on the part of the designer. Due to the difference in the understanding and standards of surge chambers between China and other countries, it is essential to study the conditions for the set-up of surge chambers. With the design of San Pablo Hydropower Station in Costa Rica as an example, based on the principles of setting up surge chambers, early and current domestic requirements for the set-up of surge chambers are discussed, and the necessity of setting up a surge chamber in the station is analyzed according to overseas set-up conditions and control standards.