Objective To explore the influence of family function and its associated dimensions on stress reaction in adolescents. Methods A total of 95 secondary vocational school students (aged 16-19 years, including 41 males and 54 females) were selected. Family function was assessed by family assessment device (FAD). Current mental status and life events were assessed by center for epidemiological studies depression scale (CES-D), state-trait anxiety inventory (STAI) and adolescent self-rating life event checklist (ASLEC). The stress reaction was evaluated by the modified Trier social stress test (TSST). The whole process of TSST was divided into 3 parts:basic state (relaxation and rest), on-the-spot speech and oral arithmetic, and recovery of calm. Saliva samples were collected before TSST and 0, 15, 30 min after TSST, and salivary cortisol level was detected by enzyme-linked immunosorbent assay (ELISA). Results Significant differences were found in salivary cortisol levels among the 4 time points (pre- and 0, 15, 30 min post-TSST) (P<0.05), indicating that the modified TSST was successfully established. Salivary cortisol levels of pre- and 0, 30 min post-TSST had a significant correlation with communication dimension of family function (r=0.231, 0.323 and 0.229, all P<0.05), and salivary cortisol level of 0 min post-TSST had a positive correlation with affective reaction (r=0.261, P<0.05). Stress situations reflected by the TSST had no significant correlation with age, gender, mental state (depression and anxiety), life events, or socioeconomic indexes of parents (marital status, economic status, employment, and educational background). Conclusion Adolescents with poor family communication have a higher level of basic stress, and the adolescents with poor family affective reaction had stronger immediate stress reaction.