Abstract: A new experimental diffractometry to determine the structure of aqueous electrolyte solution with θ-2θ type powder diffractometer has been described The super thick liquid sample cells with the isothermal function have been designed and the correction procedures for the diffraction intensity of window on the cell were proposed Computer programs for the analysis of data on X-ray diffraction by liquid and the refinement of structure parameters have been developed, based on Johansson's and Yamaguchi's works A very satisfactory experimental result of molten salt of hexaquamanganese nitrate has been obtained The comparision between the radial distribution function curve from θ-2θ type diffractometer and the free surbace scattering from θ-θ liquid deffractometer show that the resolveng power has improved.