Objective: To explore the possible latent classes and transition characteristics of medical freshmen and their relationship with social support and mental resilience, so as to provide a scientific reference for preventive education. Methods: A total of 1 155 medical freshmen were cluster random sampled from 3 medical universities in Fujian Province and received 2 rounds of surveys(T1, October 2022; T2, December 2022) by applying Student Adaptation to College Questionnaire, Child and Adolescent Social Support Scale and Connor-Davidson Resilience Scale. And the relevant data was analyzed by using latent profile analysis, latent transition analysis and multiple Logistic regression. Results: There were three different subgroups of school adjustment at two time points for T1 and T2, including high school adjustment group (34.0%, 19.8%), mild school adjustment group (60.5%, 53.8%) and low school adjustment group (5.5%, 26.4%). The low school adjustment group, relatively stable, had the greatest probability of remaining in the same group(94.0%). The high school adjustment group tended to change to mild school adjustment group(25.0%), and the mild school adjustment group tended to change to low school adjustment group (22.0%). Affected by social support, high school adjustment group was less likely to transfer to be mild school adjustment group (OR=0.40) and low school adjustment group (OR=0.26). The mild school adjustment group was prone to transfer to be high school adjustment group (OR=1.47), and less likely to be low school adjustment group (OR=0.58). Influenced by mental resilence, high school adjustment group was less likely to transfer to be mild school adjustment group (OR=0.20) and low school adjustment group (OR=0.13). The mild school adjustment group was prone to transfer to be high school adjustment group (OR=9.17), and less likely to be low school adjustment group (OR=0.42). The low school adjustment group was more likely to transfer to be high school adjustment group(OR=5.43)(P<0.05). Conclusions There are three subgroups of school adjustment in medical freshmen, and class transition in school adjustment are at higher risk and are influenced by social support and mental resilience. The social support and resilience of medical freshmen should be enhanced to promote the school adjustment.