Single electron transistor (SET) is considered as one of the most promising nanoelectronic devices for its nanoscale dimension and ultralow power consumption. Roomtemperature operation and the precise controllability of the device structure are the key issues for the widespread use of SET. The dominant fabrication techniques of the roomtemperature single electron transistor (RTSET) are the topdown process and the bottomup process. The topdown process is convenient for the integration of SETs,but difficult to control the error of the nanostructures and the characteristics of  SETs; the bottomup process is easy to make SET operate at room temperature,but also hard to reduce the error of the coupling structures in SETs. The next key to study is bring new nanostructure fabrication methods to improve the precision of the SET process based on both the topdown and bottomup processes.