A core challenge in the deepening of current Chinese teaching reform is how to transform integrated unit teaching from “experience-based design” to “evidence-based practice”. Taking the 8th Unit “Interesting Stories” in Grade 3 Volume 2 as a case, this research focuses on constructing a teaching closed loop of “data diagnosis—strategy optimization—hierarchical implementation—dynamic evaluation”. Multi-source data, including questionnaires, classroom observations, and homework analysis, comprehensively diagnose students’ difficulties in retelling ability and story creation, and explore precise implementation approaches such as scaffold construction, task-driven learning, and hierarchical homework in teaching. Data-driven unit teaching achieves a leap from “vague experience” to “precise student profiling”, a transformation from “unified teaching” to “hierarchical empowerment”, and an upgrade from “result-oriented evaluation” to “process-oriented value-added assessment”. This research proposes operable strategies, including the “three-stage model for retelling ability cultivation”, the “four-step method for character shaping in fairy tale creation,” and the “three strategies for hierarchical homework design”, providing an evidence-based practice example for integrated Chinese unit teaching.