Objective: To identify potential categories of perceived social support for middle school students and further analyze the association of different categories with bullying defender and depressive symptoms, so as to provide a reference for promoting protection for primary school bullying and reducing depression. Methods: From September to November 2021, a total of 1 021 junior high school students and senior high school students from there middle schools in Liaoning Province by convenient whole group sampling method were taken as the object of the research. Students completed the Multidimensional Scale of Perceived Social Support (MSPSS), Participant Role Questionnaire (PRQ) and Self rating Depression Scale (SDS). Latent Profile Analysis, the R3STEP method and the DU3STEP method and Logistic regression analysis were used to analyze the data. Results: Middle school students perceived social support was classified into four potential categories: low perceived social support group (8.03%, 82), perceived friendship support group(15.38%, 157), moderate perceived social support group (35.26%, 360) and high perceived social support group(41.33%, 422). Logistic regression analysis showed that girls and junior high school students had greater proportions in the perceived friendship support group( OR=0.65, 0.52, P <0.05). There were significant differences in bullying defender and depression symptom among middle school students among different potential categories of perceived social support ( χ 2=47.99, 48.80, P <0.01). The score of bullying defending the low perceived social support group was the lowest(33.75±0.82), but the highest in depressive symptoms(49.82±0.72). Conclusion There is heterogeneity in perceived social support among middle school students. By consciously improving the level of perceived social support for middle school students, families and schools can effectively promote bullying defender and reduce depressive symptoms.