[Introduction] The steam parameters of sodium-cooled fast reactor is different from PWR nuclear power or conventional fossil-fuel power plant, so it's necessary to restudy the drain system. [Method] Specific to PWR nuclear power plant or conventional fossil-fuel power plant, the steam drain system was collated and discussed from aspects such as the components and control logic. [Result] Then an optimized system is developed for fast reactor power unit based on the above analysis result and the characteristics of the steam system. [Conclusion] The result shows that the optimized drain system can meet with the requirement of fast reactor power unit, and it also can be a reference for construction of future reactor units.