Petroleum is a political goods and strategic material, which is influenced easily by some factors, such as politic, economic and military factors.According to the nature and connotation of national petroleum security (NPS) and the principles of establishment of index system, this paper selects 16 indices from five aspects and establishes an index system for appraising NPS.The index system of appraising NPS is made up of four layers, five subsystems and 16 indices.This paper firstly explains the 16 indices and gives their calculating formulas.Then on the basis of classification and quantification of the indices, this paper uses the Analytical Hierarchy Process (AHP) to determine the weight coefficient and revises it by using entropy technique with the following formula:λ_j=μ_jw_j[]∑n[]j=1μ_jw_j Where λ_j stands for the modified weight coefficient by using entropy technique,μ_j is the information weight and w_j is the weight coefficient determined by AHP.Some inspiration we can get from the studies is as follows: (1) NPS appraising is a difficult work.The selection and value calculation of indices and the determination of the weight coefficient all need researcher's personal judgment.So, a good index system needs a professional researcher; (2) we try to convert some important indices that are very difficult for quantifying into semi-quantified indices; and (3) the result is satisfied by using entropy technique to revise the coefficient.