〔Abstract〕 Objective To explore the clinical efficacy of transcranial direct current stimulation (tDCS) in the treatment of poststroke cognitive impairment (PSCI) patients and its impact on the levels of serum nerve injury markers. Methods A total of 62 PSCI patients admitted to Affiliated Rehabilitation Hospital of Fujian University of Traditional Chinese Medicine from June 2021 to March 2023 were randomly divided into an observation group and a control group, with 31 cases in each group. The observation group received basic treatment synchronized with tDCS stimulation, while the control group received basic treatment synchronized with tDCS false stimulation, for a total of 4 weeks of continuous treatment. Two groups of patients were compared in terms of clinical efficacy, cognitive function, daily living ability, nerve injury markers, and inflammatory index levels. Results The total clinical efficiency of the observation group was higher than that of the control group, and the difference was statistically significant (P < 0.05). After treatment, the scores of the mini-mental state examination (MMSE), Montreal cognitive assessment (MoCA) and modified Barthel index (MBI) of the two groups of patients were higher than those before treatment, and these indexes in the observation group were higher than those in the control group, with statistical significances (P < 0.05). After treatment, the two groups patients levels of S100β protein, interleukin-6 (IL-6), and neurone specific enolase (NSE) were lower than those before treatment, and these indexes in the observation group was lower than those in the control group, with statistical significances (P < 0.05). Conclusion TDCS can significantly improve the cognitive function and daily living activities of PSCI patients, enhance clinical efficacy, which may be related to regulating the level of nerve injury markers, thereby promoting the recovery of nerve injury.