Abstract: Qualitative longitudinal research collects qualitative data from the same group of participants across time to track and analyze the evolutionary process and deep-rooted mechanisms in their life course, psychological cognition and social practices. Qualitative longitudinal research transforms ‘time’ and ‘change’ from a static context to a dynamic focus of analysis, and emphasizes the intertwining and interaction between fixed and fluid time. Data collection methods such as repeated in-depth interviews and participant observation, and data analysis methods such as Three-strand analysis and trajectory analysis were used in order to reveal the process of meaning reconstruction of individuals over time, and to portray the non-linear characteristics and key turning points of their change trajectories. However, qualitative longitudinal studies still face many challenges such as sample loss and data management difficulties. In the future, we need to integrate innovative techniques such as digital trace mining and longitudinal mixed methods in order to build a more dynamic, complete and verifiable framework for analyzing ‘change’. Qualitative longitudinal research provides new ideas for understanding the complex and dynamic processes of psychological adaptation, crisis intervention and life course, and for constructing more explanatory and ecologically valid research pathways.

Key words: qualitative longitudinal research, temporal dimension, mechanisms of change, methodological innovation