Rising global mean temperature has been accompanied by changes in the extreme weather and climate variability. The implementation of adaptation action plans in various sectors is currently one of the top priorities in Taiwanese governmental policy agenda against climate change impacts. The electric sector plays the key role of climate adaptation in the energy industry. Risk assessment of impact of climate change on Taiwan electric system identifies extreme rainfall events from both typhoon and heavy downpour are the major risks. How to cope with the possible impacts of these extreme events and prepare appropriate adaptation is a necessary and urgent task for the utility company. The study identifies and analyses the risk of the extreme rainfall events and formulates appropriate actions for flood risk management adaptation for the sector. We adopt the framework of decision making under risk and uncertainty and carry out a stochastic cost and benefit analysis for the flood risk management. Current and future Impacts of weather and climate change on power sectors are prioritized by the multi-criteria analysis to assess the vulnerability of the power system. Appropriate adaptation actions for the electricity sector are presented. Finally, we mainstream our flood adaptation actions into the risk management of the utility company, Taipower. Our study can contribute significantly to the risk reduction on the flood impact of climate change and to the design of adaptation actions for the Taiwan electric sector.