A compact soft x-ray and extreme ultraviolet （EUV）reflectometer system using a laser produced-plasma (LPP) light source with liquid-jet target have been built based on the requirement on high-precision reflectance measurement of multilayer mirrors for use in an EUV imager which is a payload of CHANGE plan. This reflectometer is mainly composed of a LPP light source

Mcpherson 247 type grazing-incidence monochromator with moving exit slit and correlative data collection system. The monochromator have 1-125nm wavelength range and less than 0.08nm spectral resolution. In comparison with metal target LPP source

the usage of debris-free liquid-jet target LPP source avoid destroying optical elements near the light source

while the use of grazing-incidence monochromator with moving exit slit improve both wavelength range and spectral resolution. At the same time the measurement results of Mo/Si multilayer coatings reflectance with central wavelength 13.5nm and 30.4nm also are given. The curves of reflectance Vs. wavelength of Mo/Si multilayer coatings show the repeatability of the reflectance measurement is better than ±0.5%.