Abstract: Aim at the long period, complex process and strong subjectivity of experts in the traditional risk assessing procedure of civil aviation information system, a method based on AHP and improved D-S evidence theory is proposed. Firstly, the weights of each layer of factors relative to the upper layer are determined basing on AHP,and then a fuzzy comprehensive evaluation is used to give the commentary membership matrix of the lowest level factors; After that, through D-S synthesis algorithm based on matrix analysis and information entropy, the degree of conflict K between evidences is calculated and the evidence is re-weighted, obtaining the supporting degree of evidence for each factor; Final security level of the system is determined by comprehensive calculation.Compared with the widely used traditional fuzzy comprehensive evaluation method, the proposed method further decreases the expert subjectivity and is more efficient and easier to operate for safety risk assessment of civil aviation information system.

Key words: AHP, D-S evidence theory, fuzzy comprehensive evaluation, membership matrix, information entropy