Abstract: lightning risk degree is an integrated index to reflect the harmful level of lightning disasters.Based on data from ADTD (Active Divectory Topology Diagrammer) lightning location system,observation of annual thunderstorm days,investigation of lightning disaster,detection of 1679 lightning protection units,topography and geomorphology,the lightning risk degree in Dalian region was studied using an extenics comprehensive evaluation method.The result shows that the extenics comprehensive evaluation system of lightning risk degree is established based on field investigation data.There are 12 indexes in the evaluation system selected from 3 aspects which influence the degree of lightning risk,i.e.lightning activity characteristics,disaster prevention and reduction capabilities and the present situation to be evaluated.The classical and segment fields of lightning risk degree are determined using an associated function and the matter-element theory.In addition,the weighting coefficients of each evaluation index are defined based on the entropy weighting theory.The lightning risk degree in Dalian region is divided.Through typical example validation,it indicates that this method established in this paper is reasonable and practical.