Objective： To explore the distribution of T lymphocyte subsets in peripheral blood of patients with mantle cell lymphoma（MCL），and evaluate correlation with clinical baseline characteristics and its prognostic value. Methods：The clinical data of 92 newly diagnosed MCL patients from 2006 to 2017 were analyzed retrospectively. The prognostic stratification was performed using a simplified MCL international prognostic index sMIPI. The T lymphocyte subsets，including the absolute number of CD4+ T lymphocytes（ACD4C）and the absolute number of CD8+ T lymphocytes（ACD8C）were analyzed by flow cytometry. Comparisons of T lymphocyte subsets as continuous parameters in different groups were described using Mann-Whitney U test and Kruskal-Wallis. Kaplan-Meier method was used to survival analysis，and the Cox proportional hazards models were used for the estimation of prognostic factors. Results：The median follow-up was 51 months（12-150 months），and the median overall survival（OS）in 92 patients was 44 months. The OS rate at 1，3 and 5 years was 72%，45% and 37%，respectively. In our cohort，patients with high ACD4C（>0.5×109/L）had longer PFS and OS（P=0.009，P=0.004），while patients with low CD4+/CD8+ ratio（≤1.2）had unfavorable PFS and OS（P=0.025，P=0.009）. Univariate Cox regression indicated that ECOG ≥2（P=0.021），B symptoms（fever，night sweats or weight loss）（P=0.001），elevated LDH（P=0.027），high sMIPI score（P=0.004），low ACD4C（P=0.013）and low CD4+/CD8+ ratio（P=0.030）correlated with shorter PFS，while the inferior OS was associated with B symptoms（P<0.001），high sMIPI score（P=0.004），elevated LDH（P=0.040），low ACD4C（P=0.006）and low CD4-/CD8+ ratio（P=0.012）. Multivariate Cox regression showed that B symptoms（P=0.006）and low ACD4C（P=0.001）were the independent prognostic factors of PFS；B symptoms（P=0.003），high sMIPI score（P=0.047），low ACD4C（P=0.001），low CD4+/CD8+ ratio（P=0.031）were the independent prognostic factors of OS. Conclusion：Low ACD4C and low CD4+/CD8+ ratio were associated with unfavorable prognosis in MCL patients. ACD4C level and CD4+/CD8+ ratio proved to be convenient and effective predictors of prognosis in patients with MCL.