The Deang have been followers of Theravada Buddhism since the Ming Dynasty, when they came under Dai rule.

However, they have retained a number of the features of their indigenous religions in such a way that during the year both Animist and Buddhist festivities are still held. Sometimes, components from both traditions are found in important events, such as sowing, or when someone dies.

According to one of their legends, Sakyamuni and the Goddess of the Rice held a competition. Even though Sakyamuni won, he realized that, without the products of the land, which depended on the intervention of the Goddess of Rice, he would not get any offerings, so both deities reconciled. This might explain why in every person's heart both traditions coexist. Buddhism, used to solve the complex questions concerning human existence; and Animism, used to ensure this very existence.

There is a Buddhist temple in almost every village. But these coexist alongside a great number of nature sites, such as trees, that symbolize the different deities of the Deang traditional pantheon.

As well as the Goddess of the Rice, who is worshipped all year round, during every single harvesting period they worship another five gods in order to ensure good crops:

- The God of the Land, who is in charge of ensuring the productivity of the land.
- The Dragon God, who is in charge of the proper distribution of wind and rain.
- The God of the Village, who looks after everyone.
- The God of Heaven, who is responsible for the creation of the Deang.
- The Snake God, who makes sure that reptiles do not harm people.

According to Deang traditional belief, if people are good, they will be rewarded by going to heaven. If they are bad, they will go to hell. According to Deang spiritual understanding, there is a world of yin and another of yang, corresponding to traditional Daoist thought. The first is the world of shadow and the second of light. When people die, they must travel from the world of light to the shadow world crossing, envisioned as a long river. This is why they bury their dead in boat-shaped coffins, which will help their souls to cross this river and arrive at the world of shadow.

As for Buddhism, its influence has been unequal among the different Deang branches. All them, however, do share some common characteristics: villages have a temple which is both a school and a place of worship; with monks who know how to read the Buddhist writings in Dai language acting as teachers. Novices study in the temples. Both monks and novices are fed by the villagers.

But there are also some differences among the Deang branches, or the three ethnic groups included under the name "Deang", and we see that:

Among the Rumei ethnic group, the religious Buddhist schools are usually not very strict and there is harmony between Buddhism and the traditional religions.

Among the Bulei ethnic group, the Buddhist schools are very strict and many villages do not eat meat nor raise domestic animals. Many have given up their traditional celebrations and do not even drive away wild animals that enter their fields.

Among the Liang ethnic group, in some areas, like Zhengkai, the influence of Buddhism has been very superficial. In others, the most orthodox Buddhist schools have caused significant changes in their daily lives and culture.