Abstract: Peking University is planning to put up a FEL facility�PKU-FEL, which will be used as a tool for experimental studies on nonlinear transient physical process, chemical kinetics, molecular biology, material science, etc. Based on PKU-SCAF, a superconducting accelerator facility, PKU-FEL has the characteristics of high stability and high average power. Moreover, wavelength of PKU-FEL will cover the band from about 3 to 23μm and the pulse duration will be about 2ps. This paper gives a brief description of the design considerations．