Objective: To explore the characteristics and relationships of achievement goal orientation,academic social comparison and academic self-efficacy of middle school students.Methods: 343 middle school students were assessed by Achievement Goal Orientation Scale,Social Comparison Scale and Academic Self-efficacy Scale.Results: ①In the way of comparison,boys used more down-comparison than girls,and in the results of comparison,boys had lower scores on self-improvement than girls.②Students with higher academic achievement used more mastery approach goal orientation and mastery avoidance goal orientation.③Students with higher academic achievement used more upward-comparison and parallel-comparison,while students with poorer academic achievement tended to use downward-comparison.④The influence of achievement goal orientation on academic self-efficacy was partly mediated by academic social comparison.Conclusion: Different gender and academic achievement of middle school students have different means of academic social comparison.Academic social comparison plays an important mediating role in the relationship between achievement goal orientation and academic self-efficacy.