Objective To explore the effect of transcranial direct current stimulation（ tDCS） on spatial working memory in schizophrenic patients with tardive dyskinesia（ TD）. Methods A total of 38 schizophrenic patients with TD from Suzhou Guangji Hospital， Suzhou Social Welfare Home， Nanchong Physical and Mental Hospital， and Taicang Third People's Hospital were randomly divided into trail group（ 21 cases） and control group（ 17 cases）. Both groups received conventional medication therapy. The trail group received tDCS with a current of 2 mA at the left dorsolateral prefrontal cortex and the contralateral supraorbital margin. The control group was treated with sham tDCS for 3 weeks. The patients were followed up at baseline， after the 15th treatment and 2 weeks after treatment. The Spatial Working Memory（ SWM） module of the Cambridge Neuropsychological Test Automatic Battery（ CANTAB） was used to evaluate the cognition of the patients in both groups. Results After 15 treatments， the total number of errors［ 31.00（ 28.50，49.00）］， the average first response time（ 4 boxes）［ 3 289.500（ 1 871.750，5 018.000）ms］， the average first response time（ 6 boxes）［2 862.500（ 2 128.500，4 672.250）ms］， the average first response time（ 8 boxes）［ 3 328.500（ 2 611.250， 5 120.750）ms］， has no statistically significant difference compared with those of the control group（ P＞0.05）. The strategy score of SWM index analysis in the experimental group［ 19.00（ 17.00，20.00）］ was lower than that in the control group［ 21.00（19.50，23.00）］. The difference was statistically significant（ P＜0.05）. In the followup after 2 weeks， there was no statistically significant difference in SWM between the two groups（ P＞ 0.05）. Conclusions There may be immediate improvement effect of tDCS on the ability of schizophrenic patients to use strategies.