Rough set theory is conceived as an effective mathematical tool to deal with uncertain information. However, rough set is not suitable to deal with dynamic data, some methods are proposed to solve this question. Evolution model of granular decision is an extension for time series sets based on classical rough set model. Its purpose is to research the rules of decision on time series. Evolution model of granular changes the focus from static decision information system to dynamic time series. It researches the regulations of evolution in decision information system which will be changed in time series. It is a new method to research decision information system. Evolution model of granular decision has the unique advantage in application, but it does not have the clear concept for classification of attributes. This paper gives a concept for decision evolution set based on evolution model of granular decision, and researches its effects in application.