Since the first lasing in March 2005 in CAEP, the FEL-THz facility has been updated, the former thermionic cathode injector has been replaced by a high brightness photo-cathode injector. The facility mainly consists of a 4.5 cells photo-cathode RF-gun injector, a hybrid undulator and the optical oscillator cavity. The parameters are as followed: number of undulator periods:44; the peak value of the undulator:0.49 T; the good aperture:6 mm; the cathode material:Cs2Te；the quadruple light was used；the width of the driving laser:12 ps；the quantum efficiency:about 1%. The commissioning of the injector has been finished; the electron energy of the injector has been measured and it is about 8 MeV with the energy spread about 1%, and the electron beam normalized emittance about 9 ?mm?mrad. The charge is about 100 pC and up to 1nC per micro-pulse, the repetition rate is 54.167 MHz. The calculated wavelength of the light is about 125 micron. At present, the spontaneous emission experiment is undertaking.