Abstract: To solve the decision-making problem based on results of multi-source information fusion and D-S evidence structure, a decision-making method based on distance measure is proposed. The method combines attributes of decision-making basic elements with that of decision-making non-basic elements to make a decision about the results, and divides the problem on D-S evidence into two levels, that is, attribute level and evidence level. On the attribute level, a method for obtaining support degrees of candidate decision-making focal elements from evidence focal elements is introduced. On the evidence level, a space based on power set elements of the discernment frame is generated, ideal state vectors of candidate decision-making focal elements are introduced, distance measure is defined, and a decision-making model based on the measure is made. Finally, the fusion results of multi-source information about water quality monitoring data are analyzed based on different methods. The result indicates that the decision-making method based on distance measure is valid and has advantages of processing conflict evidence or non-conflict evidence.