Mixed method research refers to the use of qualitative and quantitative research methods to collect and analyze data, integrate research findings and make inferences in a single study or a research protocol. Integration is the core of mixed method research, which runs through all aspects of mixed method research, including 15 dimensions such as philosophical position, theoretical dimension, research team, research design, sampling, data collection and analysis, and results presentation. This paper briefly introduces the integration of four dimensions: research design, sampling, data integration and results presentation.