An experimental method is reported in this paper for X-ray measuringement of liquid structure by X-ray reflection of from flat specimen cell with a the five-circle goniometer in of the 4W1C beamline of Beijing Synchro-tron Radiation Facility(BSRF I) was reported in the paper.Taking the scattering measurement of an aqueous solution of sodium sulfate for as an example

construction of liquid cell

scattering geometrical arrangement

sample alignment

and scanning mode were briefly introduced.Corrections of the measured scattering intensity for such as net absorp-tion of beryllium window

air scattering

synchrotron radiation polarization

sample absorption and geometrical factor

etc.were described in detail.Calculation procedures of liquid structural function and radial distribution function

in-cluding removal of Compton scattering and spurious peak

were demonstrated.The result shows that high quality X-ray scattering data can be obtained by the X-ray reflection method.