Objective To explore the role of T-lymphocyte subsets （CD3+ ， CD4+ ， CD8+ ， CD4+ / CD8+ ） in early recognition of neurosyphilis. Methods A total of 100 patients with syphilis in Department of Neurology， Xixi Hospital of Hangzhou from February 2020 to January 2022 were retrospectively analyzed. There were 50 cases in neurosyphilis group and 50 cases in non-neurosyphilis group. 50 health examinees from our hospital in the same period were selected as the control group. The levels of CD3+ ， CD4+ ， CD8+ of T-lymphocyte and the ratio of CD4+ /CD8+ were compared among the three groups. The value of T-lymphocyte subsets in peripheral blood in identifying early neurosyphilis was analyzed by using the receiver operating characteristic （ROC） curve. Results The levels of CD4+ T-lymphocytes in the neurosyphilis group， the non neurosyphilis group and the control group were （30.48±4.08）%， （32.16±4.08）% and （34.50±4.49）%， respectively， and the CD4+ /CD8+ ratios were （1.25±0.19）， （1.35±0.25） and （1.47±0.23）， respectively. The differences among the three groups were statistically significant （F=11.428， 11.970； P ＜ 0.01）. The differences between every two groups were statistically significant （P＜ 0.05）. The patients in neurosyphilis group were divided into early group （n=30） and late group （n=20） and compared with the control group. The results showed that the levels of CD4+ T-lymphocytes were （31.23±4.28）%， （29.35±3.57）%， （34.50±4.49）%， and the CD4+ /CD8+ ratios were （1.29±0.21）， （1.18±0.13）， （1.47±0.23）， respectively. There was a statistically significant difference among the three groups （F=12.289， 15.350； P＜ 0.01）. The CD4+ T-lymphocyte level and CD4+ /CD8+ ratio in the late stage group were lower than those in the control group， and the CD4+ /CD8+ ratio was lower than those in the early stage group， with statistically significant differences （P ＜ 0.05）. The area under the ROC curve （AUC） predicted by CD4+ /CD8+ ratio was 0.725 （95%CI：0.645-0.805）， higher than that of CD3+ ， CD4+ and CD8+ . Conclusions The significant decrease of CD4+ level or CD4+ / CD8+ ratio is highly suggestive of neurosyphilis， CD4+ / CD8+ is more helpful for early identification of neurosyphilis.