Daily interaction is a primary means of understanding social change which is of vital importance for community well-being. In tourism host communities, daily interactions among different resident groups reflect tourism’s effects which are directly related to tourists’ experiences and community harmony. In this exploratory article, grounded theory was applied to analyze daily interactions between locals and migrants in Zhouzhuang, the first ancient tourism town in China, based on in-depth interviews. A model framework was also constructed. The results pinpoint subjective interaction intention and objective interaction opportunities as two influencing factors which operate reciprocally and directly influence locals’ and migrants’ daily interactions. The findings suggest that many locals and migrants experience clear communication boundaries in daily interactions. Both groups’ subjective interaction intentions were influenced by their cultural backgrounds, group perceptions, and original social networks, all of which are difficult to modify within a short time. Therefore, increasing objective communication opportunities is a key way to promote intergroup interaction and integration. These findings provide theoretical and practical implications for tourism host communities’ well-being and sustainable development.