Abstract: AHP method can be used to solve problems in multi-criterion decision systems with its special advantages.However, some complicated problems cannot be easily solved with general methods after AHP analysis, because either the complicated tasks are unable to be solved by AHP as they do not satisfy the consistency condition or the estimated matrix is too intricate to solve so that AHP is invalidated.To deal with such problems, the AHP knowledge system is reduced with the aid of GA.The issue of AHP ordering is then solved with the RST method, or problems are reduced by RST still with classical AHP method.Thus, in addition to the four rules in changing an AHP system into an RST decision system, the comparison decision system of region informatization level is solved using this method, and the results solved are the same as that obtained by classical AHP, indicating that the method is simpler and more reliable.

Key words: rough sets theory (RST), region informatization level, analytic hierarchy process (AHP), genetic algorithms (GA)