As a large energy consumer and importer，energy reserve is vital for Japan’s energy security. Japan built its energy reserve from 1960s. With economic development and international energy market dynamics，Japan’s energy reserve strategy has continued to perfect. Since 1980s，natural gas and nuclear power have developed at a fast pace，and these energy sources have been lifted to the policy level in Japan’s energy reserve strategy. Japan has built natural gas and nuclear power reserve systems after its oil reserve system. Energy reserve strategy such as oil reserve helps Japan to increase energy security.