As a new research method for decision rules, decision evolution set is the theory to deal with evolution problems of decision rules in time series, which transfers the focus from static information system to dynamic time series and studies the time-dependent evolution regulations of decision information systems. At present, the evolution trace defined by normal structure of decision evolution set is a graph in n-dimensional space, which is difficult to describe. So the membrane structure is newly proposed in this paper to describe the decision evolution set. In the membrane structure, the reduced attributes are got attention in the same way. When the time goes from point t i-1 to point ti, attributes will enter different membranes based on their influence to decision and the data flow made in the process will be labelled at the same time. Thereby the problem of evolution trajectory visualization for decision information system is then solved. And the evolution process and trace of decision evolution system has been demonstrated by using some samples.