To satisfy the requirements of 13.9 nm Ni-like Ag and 19.6 nm Ne-like Ge X-ray laser researches,Mo/Si multilayer mirrors were prepared,and a small and simple structure reflectometer easy to operation was designed.A reflectivity-measuring system consisting of a reflectometer,a Mcpherson 247 monochromator and a Extreme Ultraviolet(EUV)radiation source from copper-target Laser Produced Plasmas(LPP) was established.The calibration precision of the monochromator was 0.08 nm and the intensity variance of the LLP source was lower than 5%.The experimental results show that the reflectivities of Mo/Si multilayer mirror at 13.9 and 19.6 nm are 41.9% and 22.6%,the related FWHMs are 0.56 and 1.70 nm,respectively.The measurement of surface roughness was carried out using WYKO,which are 0.52 nm for 13.9 and 0.55 nm for 19.6 nm.