学情分析是教学设计的起点，新课程改革以来，教师逐步认识到在提升教学有效性过程中必须关注学情，但是在实际的教学设计中仍然存在着依靠主观经验进行学情分析，教学设计起点不清晰的问题。本文以人教版《高中地理（必修一）》“昼夜长短的变化”一节为例，以大学生教育实习中教学设计指导为基础，说明学情分析的具体过程与方法，探讨了如何根据学情进行教学设计进而保证课堂教学有效性的问题。旨在以此为广大地理教师科学进行学情分析提供参照。

The analysis of student situations is the beginning of teaching design. Since from the new curriculum reform, The teacher gradually realized that in order to enhance teaching effectiveness process they must pay attention to student situations. But in practical instructional design ，there still depend on subjective experience to carry on the problem of teaching design which is not clear for the analysis of student situations. In this paper, I take the example of The change of the length of day and night from the PEP geographic textbook（ Compulsory 1），the base is the guidance of teaching design in students' education practice. It illustrate the specific process in student situations. The paper has discussed the problems about how to ensure the effectiveness of classroom teaching and how to improve it according to student’s circumstances. The paper is aimed to provide scientific reference for geography teacher in carrying on the analysis of student situations.