Abstarct: In this work, the structure of alkali liquid Cesium was by using structure factor S(k) calculations. An analytical exxpression for Fourier transform direct correlation function, c(k),which obtained by Herrera for hard-core Yukawa fluid (H-Y), used to calculate of S(k). This analytical exxpression obtained from the Ornstein-Zernike equation in the mean spherical approximation (MSA). In this work, hard-core Yukawa potential considered as an effective potential. For this purpose, the equation of state of Ghatee-Bahadori was used to calculate the Yukawa potential well depth parameters at a wide range of temperature and density. Besides, molecular diameter of H-Y was calculated by Barker-Henderson method in every temperature. Using the presented model, the behavior of structure factor of alkali liquid Cesium has been carried out in a wide range of thermodynamic states. Obtained results were compared with evaluable experimental values. Which shown a reasonable agreement especially in high densities. In addition, it was indicated that the proposed model can be predict S(0) values accurately in the dense states. Investigated the temperature and density dependency of Yukawa potential well depth in two ranges of isotherms including 400-900 K and 1000-2000 K. An equation for Yukawa potential well depth parameter was presented for T=600-900 K and T=1200-1800 K thermodynamic regions vs. temperature and density. The capability of equations obtained was investigated by predicting the structure factor of other alkali liquid mextals. Results obtained show a well agreement with the experimental data.