Mulei Kazak Autonomous County is the easternmost county of Changji Hui Autonomous Prefecture in Xinjiang Uygur Autonomous Region. It is located at the north foot of Tianshan Mountain, the southeast edge of Junggar Basin, the east of Qitai County, the west of Balikun County, the south of Tianshan Mountain and Shanshan County across the mountain, and the north of Mongolia. It has jurisdiction over 3 towns, 7 townships, and 1 ethnic township. The county seat is 270 kilometers away from Urumqi. The administrative area is 22171 square kilometers. In 2019, Mulei Kazak Autonomous County had a registered residence population of 86228.

"Mulei", also written in the Qing Dynasty as "Mulei", is the transliteration of "Pu Lei" in the Hun language. In the Western Han Dynasty, Mulai was a land of Pu-like. In the prosperous Tang Dynasty, Pulei County was under the protection of Beiting Capital, and at the end of the Tang Dynasty, it belonged to Gaochang. The Song Dynasty returned to Western Liao. The Yuan Dynasty was a nomadic land for Mongols. The Qing Dynasty was subordinate to Zhenxi Prefecture. In the sixth year of the Republic of China (1917), Muleihe County was established. In the 19th year of the Republic of China (1930), it was upgraded to a county. In 1954, Mulei Kazak Autonomous County was established under the jurisdiction of Dihua Special Region. In 1958, it was assigned to Changji Hui Autonomous Prefecture. There are Mingsha Mountain, Populus euphratica forest, forest park, Dragon King Temple, primitive villages and other tourist attractions in Mulei Kazak Autonomous County.

In 2019, the regional GDP of Mulei Kazak Autonomous County was 4025.19 million yuan, the added value of the primary industry was 1013.31 million yuan, the added value of the secondary industry was 736.01 million yuan, the general public budget revenue was 494.69 million yuan, and the general public budget expenditure was 1777.95 million yuan. In November 2021, the third batch of Xinjiang Uygur Autonomous Region's regional tourism demonstration areas will be listed.