The thesis investigates implementation problems of ethnic group formation in order to find a suitable guideline to solve the problems in Chiang Rai Province. It is found that most minority ethnic groups tend to culturally assimilate with mainstream society as can be seen from village chiefs being elected. They also dress like other lowlanders, so the changes are relatively concrete and evident. Most of the young generation have discarded their traditions and customs. The minority ethnic group formation policy is the best way to solve the problems because it is implemented gradually, creating a good relationship between ethnic highlanders and lowlanders. The implementation of the policy has been relatively successful in the province. However, some issues remain problematic to the implementation. They include narcotic drugs, migration, and verification of the status of highlanders. If these problems are not solved, they may have negative ramifications on the society (pp. 75-77, 99-101).