Abstract: Regarding the characteristics of complicated pore types and strong heterogeneity of carbonate reservoirs and based on the exploration status of fluid properties difficult to be predicted in Tarim basin, DEM-Gassmann rock-physics model which not only considers the influence of pore shapes on velocity but also diminishes velocity dispersion by differential method was employed for fluid substitution in the carbonate reservoirs in Wellblock ZG8, Tazhong area. It was concluded that the elastic properties of the water in the reservoir were different from those of oil and gas. Based on the comparison of elastic parameter crossplots, P-impedance vs. Vp/Vs and Poisson ratio vs. P-impedance were selected to identify fluid properties, and according to AVO inversion results, fluid property prediction was carried out for the carbonate reservoir in Yingshan formation of Wellblock ZG8. The predicted results were in accordance with the geological understanding obtained from 24 wells. Theoretical and case analysis in this paper provide some applicable methods and corresponding standards for the fluid prediction in the caved carbonate reservoirs in Tarim basin.