Recent researches on the quality of consumption behaviors were mainly focused on the consumer's side. However, as the consumption behavior is a two-way interactions of consumer and service provider, increasing understanding of the service provider might also beneficial for improving service quality. In-depth interview might be an appropriate method in exploring the social psychological development of the service provider. The implication, the purpose, the sampling procedure, the role of interviewer, the research process, the principles of data analysis, together with the strengthnesses and weaknesses of qualitative research and in-depth interview are instroduced in this paper.