They believe the soul of their ancestors will bless them. For this reason they thank their ancestors during the harvest season and pray for a good harvest the following year. Hunting a man's head for worshipping and many of the taboos in daily lives are some of the customs set by their ancestors. If anyone disobey the orders, disasters will happen to his family or even the whole village. To them certain plants and animals have spirits and are not to be eaten but worshipped.
Witches treat patients and pray for rain or sun.
When Holland ruled Taiwan, many missionaries evangelized among the Gaoshan. In 1661, the missionaries were driven away or killed and churches destroyed. The Gaoshan returned to their former religions.