This thesis investigated migration and ethnic identity maintenance of Plang residents in Langzhai Village, Sipsongpanna Region, China, who migrated into Thailand. The data were collected by interviewing the villagers and migrant laborers in Bangkok. It was found that the migration into Thailand took place in three periods: during the battle between the Kuomintang Party and the Communist Party, during the Cultural Revolution and Land Reform, and after 1990. The main purpose of their migration was to earn more income for their families. The Plang preferred to migrate into Thailand rather than to other cities in China, because Thailand still needed more labor, the ethnic language is in the same family, and they are Theravada Buddhists like Thais. Furthermore, they could hardly speak Chinese and are not Mahayana Buddhists like the Chinese. To migrate into Thailand, they were assisted by middlemen who smuggled them into the country. The middlemen taught them basic Thai and found them jobs. The ethnic migrants in Bangkok formed into groups to participate in activities and to help one another like what they did in their village. Additionally, they symbolically expressed their culture to indicate their ethnicity from their village, such as group administration or wearing shirts with the symbol of the Chinese flag, even though they were not in the status to express themselves openly. The migrant laborers were both men and women. However, female laborers usually got unskilled jobs and were paid less than their male counterparts, thus obliging them to work overtime in order to send home as much money as they could. Some men often entertained themselves on weekends and were involved in illegal activities. Despite getting higher pay than women, they ended up sending less money home than the women did. In the past, villagers were able to produce enough rice for domestic consumption without extra money for disposal. After migrating to work in Thailand, they were able to buy electrical appliances and other equipment for personal comfort. Consequently, they liked to migrate to find work in Thailand even though they were illegal foreign migrants and had to escape from being arrested. Besides the above changes, migration negatively affected family relationship and couples. It was found that this economic migration had become a major cause of divorce in many families.