The live-line works are very dangerous because of direct contacts with the distribution line or neighboring contacts. So the purpose of this study is to identify the risk factor by accident occurrence form and accident case analysis, and to suggest the quantified risk index by risk occurrence frequency and risk strength analysis. And the risk index assessment is researched by accident cases analysis on work type. Accident cases of transmission· distribution line are researched based on data of the Ministry of Employment and Labor in the last ten-year period (2000~2009). In results of this paper, high risk isn`t always a priority of safety measures. Risk occurrence frequency and risk strength have to be considered according to detail work types, work methods and conditions of field work. And safety management measures must be planned according to risk occurrence frequency and risk strength.