The average annual temperature in Beijing city increased at the rate of 0.37℃ per 10 years, the intensity and range of heat island effect increased during 1951-2014. With the development of economy and society,extra pressure that climate change brings to energy supply system trends to be significant. This study focuses on the vulnerability of energy system under climate change. The vulnerabilities of climate change in the energy sector in Beijing are that electric load of power demand is over maximum load designed for power supply system under high temperature; under the condition of low temperature, natural gas supply is short; energy production,energy supply and energy transport are threatened by extreme weather. According to the vulnerabilities of the energy system of Beijing,combined with the international advanced experience, the key measures and suggestions were put forward in order to enhance the climate change adaptability of energy system in Beijing.