In Tra Vinh province where groups of ethnic living together for hundreds of years, the Khmer keep a major role in social development. With the aim of showing how strong of interethnic relations in here, this paper provides a review of ethnicity theory, in which ethnic study approaches are the focused. Besides analyzing primary documents of Khmer ethnic in Tra Vinh such as population, current living conditions, there are interviews to assess Khmer’s opinions about interethnic relations. It is important to examine diversity in relation to living conditions that may influence how Khmer respond to the ethnic diversity within Tra Vinh context.