Abstract: The current database index uses the single text feature clustering method in the indexing query on the Web database.When the clustering features are different,the illegal clustering and illegal output problems occurred．A Web database security index method was proposed based on multi-layer space fuzzy subtractive clustering．The database information vector is constructed as a multilayer vector autoregressive space．The data flow information is focused on the multi-layer fuzzy clustering centers,and the fuzzy inference system of subtractive clustering is used to establish the database index function．The clustering center vector is adjusted in variable scales．The neighboring data point’s illegal intrusion and clustering problems are avoided．The Web database security index is realized．Simulation result shows that the new algorithm can make the database information flow expanded in the multilayer vector autoregressive space．The feature matching degree is improved greatly,and illegal data output is removed．The security index can be ensured.

Key words: Web database,Fuzzy subtractive clustering,Autoregressive,Security index