As the main passageway and hub for economic and cultural exchanges between the East and the West in ancient times, Xinjiang has always been a region where a number of religions exist side by side. Before Islam was introduced into Xinjiang, there had already been believers in Zoroastrianism, Buddhism, Taoism, Manichaeism and Nestorianism. These religious faiths had spread to Xinjiang along the Silk Road and thrived together with the local primitive religions. After the introduction of Islam, the coexistence of diverse religions continued to be the order of the day in Xinjiang, to be joined later by Protestantism and Catholicism.

Before the foreign religions were introduced into Xinjiang, the ancient residents there believed in native primitive religions and the Shamanism evolved therefrom. Even today, some minority peoples in Xinjiang still adhere, to different degrees, to some of the concepts and customs characteristic of these beliefs.

Around the fourth century B.C., Zoroastrianism, or Fire Worship as it was popularly called, which was born in ancient Persia, was introduced into Xinjiang through Central Asia. It became prevalent throughout Xinjiang during the period of the Southern and Northern Dynasties and the Sui and Tang dynasties. It was particularly popular in the Turpan area. The Gaochang state of that time set up a special organ and appointed special officials to strengthen its control over the religion. Some ethnic groups in Xinjiang that followed Islam once also believed in Zoroastrianism.

Around the first century B.C., Buddhism, born in India, was introduced into Xinjiang through Kashmir. Soon after, it became the main religion in the region thanks to efforts made by the local rulers to promote it. At its peak, Buddhist temples mushroomed in the oases around the Tarim Basin with large numbers of monks and nuns. Yutian, Shule, Qiuci and Gaochang were all centers of Buddhism. In Xinjiang, Buddhist culture reached a very high level, leaving a precious cultural heritage of statues, paintings, music, dancing, temples and sacred grottoes, greatly enriching the cultural and art treasury of China and the whole world.

Around the fifth century, Taoism was introduced into Xinjiang from inland China by Han migrants. However, Taoism was limited mainly to the Turpan and Hami areas, where Han people were concentrated. It was not until the Qing Dynasty that Taoism became widespread throughout Xinjiang.

Around the sixth century, Manichaeism reached Xinjiang from Persia through Central Asia. In the middle of the ninth century, when the Uighur, who were believers in Manichaeism, moved westward to Xinjiang, they promoted the development of the religion in the region. They built temples, dug grottoes, translated scriptures, painted frescoes and spread the Manichaeist creed and culture in the Turpan area. Around the same time, Nestorianism, an earlier sect of Christianity, was introduced into Xinjiang, but it was not widespread in the early years. It flourished only when large numbers of the Uighur accepted it during the Yuan Dynasty (1206-1368).

In the late ninth century and the early 10th century, Islam spread to the south of Xinjiang through Central Asia. In the middle of the 10th century, the Islamic Karahan Kingdom waged a religious war against the Buddhist kingdom of Yutian, which lasted for more than 40 years. It conquered Yutian in the early 11th century, and introduced Islam to Hotan. In the middle of the 14th century, under the coercion of the Qagatay Khanate (a vassal state created by Qagatay, the second son of Genghis Khan, in the Western Regions), Islam gradually became the main religion for the Mongolian, Uygur, Kazak, Kirgiz and Tajik peoples in that region. In the early 16th century, Islam finally became the main religion in Xinjiang, replacing Buddhism.

After that, Zoroastrianism, Manichaeism and Nestorianism, the main religions of the Uygur and other ethnic groups, gradually went out of the picture in Xinjiang, but Buddhism and Taoism continued to make themselves felt there. Beginning in the Ming Dynasty, Tibetan Buddhism grew into a major religion on a par with Islam in Xinjiang.

In the late 17th century, Apakhoja, chief of the Aktaglik Sect of Islam, wiped out the forces of his political foe Hoja of the Karataglik Sect, by dint of Tibetan Buddhist forces, and destroyed the Yarkant Khanate (a regional regime established by Qagatay's descendants between 1514 and 1680, with modern Shache as its center). This shows how powerful Tibetan Buddhism was at that time.

Around the 18th century, Protestantism and Catholicism spread to Xinjiang, at a time when Buddhism, Taoism and Shamanism were flourishing in the region, and temples and churches of these religious faiths could be found everywhere in Xinjiang. Some Moslems even changed their faith to Christianity or other religions.

Historically, the dominance of a particular religion has kept changing from time to time in Xinjiang, but the coexistence of multiple religions following the introduction of outside religious faiths has never changed. The major religions in Xinjiang today are Islam, Buddhism (including Tibetan Buddhism), Protestantism, Catholicism and Taoism. Shamanism still has considerable influence among some ethnic groups.