From April 23 to May 3, 1947, the Inner Mongolia People's Congress was held in Wangye Temple, Ulanhot city. It was decided that May 1 is the memorial day for the establishment of Inner Mongolia autonomous region, where regional ethnic autonomy was realized for the first time in China.
Covering an area of 540,000 square kilometers, it then had jurisdiction over Hulunbuir League, Naveen Muren, Hinggan League, Xilin Gol League, Qahar League, 32 banners, one county and three county-level cities. The autonomous government was located at Wangye Temple.
In November 1949, with the approval of former premier Zhou Enlai, the government relocated to Zhangjiakou.
On Sept 19, 1949, an uprising led by Dong Qiwu, a senior general from Kuomintang and acting governor of Suiyuan province, and another 18 people broke out, giving birth to the Suiyuan Provincial People's Government.
On March 5, 1954, a conference was jointly held by the Inner Mongolia People's Government, Suiyuan Provincial People's Government Committee, Suiyuan Military Committee and Suiyuan People's Consultative Committee in Guisui city (today's Hohhot).
According to commands from the central government, Suiyuan province and Suiyuan Provincial People's Government were revoked, and the former Suiyuan provincial jurisdiction belonged to the Inner Mongolia autonomous region. The autonomous region's government was located in Hohhot.
On July 30, 1955, Aohan Banner, Ongniud Banner, Harqin Banner, Chifeng county, Ningcheng county and Wudan county of Rehe province came under the jurisdiction of the Juu Uda League of the autonomous region.
On April 3, 1956, Bayanhot Mongolia autonomous prefecture and Ejin Mongolia autonomous banner in Gansu province came within the jurisdiction the of Inner Mongolia autonomous region, forming Bayannur League, keeping the former administrative regions the same.
On July 5, 1969, Hulunbuir League, Jirem League and Juu Uda League came under the jurisdiction of Heilongjiang province, Jilin province and Liaoning province respectively. Alxa Left Banner came to the jurisdiction of Ningxia Hui autonomous region, and Alxa Right Banner and Ejin Banner to the jurisdiction of Gansu province.
On May 30, 1979, the three banners came under the jurisdiction of the Inner Mongolia autonomous region once more.