Pre-stack simultaneous inversion and CRP of pre-stack time migration provide an effective reservoir prediction approach for lithology and subtle reservoir exploration.The pre-stack simultaneous inversion formula is given according to the fundamental theory of elastic wave propagation and through simplifying the Zoeppritz equation for plane wave reflection and transmission.On the basis of well log data analysis and calculation of the elastic parameters,the utilization of P wave impedance and S wave impedance cross-plot analysis can distinguish lithology,the use of the P wave impedance and porosity can distinguish the reservoirs,and the employment of the reservoir and fluid factor λ cross-plot can distinguish oil and gas potentials of the reservoirs.The plane distributive and cross sectional characteristics of E_s1 gas and oil reservoir were discriminated directly with the inversion result,and the distributive and cross research shows that inversion is practical for the quantitative discrimination of the reservoir.