Yan 'an is one of the birthplaces of Chinese civilization for 5,000 years. Xuanyuan Huangdi's mausoleum is located on the top of Qiaoshan Mountain in Yan 'an, and the descendants of China are honored as "the ancestors of mankind". From 1935 to 1948, Yan 'an is the seat of the CPC Central Committee and the general rear of China people's liberation struggle. In June 1996, 1 15, with the approval of the State Council, Yan 'an area was abolished and a prefecture-level city was established (65,438 Yan 'an has an inland arid and semi-arid climate, with a total area of 37,000 square kilometers and a permanent population of 2,252,800 (2065,438+06) [2]. It has jurisdiction over 2 districts, 1 1 county, 16 sub-district offices, 84 towns and 12 townships [3].