Reservoirs in block Su 59 of Sulige Gas Field are controlled by sandstone distribution and physical properties, with complicated gas-water relation. So it can not identify reservoir and fluid effectively by using traditional acoustic impedance inversion method. Through detailed rock physical parameters analysis, the elastic parameter combinations sensitive to lithology were found out, and extensive elastic impedance （EEI） model was established. EEI curves which have good relationship with natural gamma ray, porosity and water saturation were used to reflect lithology, porosity and oil-bearing ability. It is meaningful for elastic parameters inversion with pre-stack seismic data and reservoir and hydrocarbon distribution prediction.