Abstract: The small reactor is expected to be applied in a wide range of fields. The small reactor with different technology routes has corresponding characteristics and priority application directions. The technical problems to be solved in small reactor with different coolants are also obviously different. For example, the main problems to be solved in sodium-cooled small reactor are the refueling cycle for more than ten years and safety of sodium-water reaction. Lead bismuth cooled small reactor needs to solve the design and engineering problems of corrosion-resistant and high-temperature resistant structural materials, protection of ²¹⁰Po, integration and miniaturization. Based on China Experimental Fast Reactor and Xiapu Demonstraion Fast Reactor technology research, a relatively mature design scheme of small sodium-cooled fast reactor was presented by China Institute of Atomic Energy (CIAE). It is one of the representative results of CIAE in the field of small reactor technology application research.