Classic rough set approach acquires knowledge by means of indiscermibility relation,but it is powerless to resolve the sequencing classification problems which contain qualitative attributes and quantitative attributes as well as criteria attribute.In this case,a decision analysis method based on extended rough set theory was proposed.The method replaces indiscemibility relation in original rough set theory with the "indiscemibility-approximation-dominance"relation and obtains rough approximation of knowledge,it will not only be able to resolve the absolved-mentioned problems but also deal with inconsistence in decision table.The experimental results the extended method of rough set theory not only can resolve the sequencing classification problems and inconsistence in decision table,but also can get more reasonable decision rules.