To explore the characteristics of cognitive impairment and its relationship with factors such as age, education, clinical symptoms, and duration of illness in depression and schizophrenia patients. Methods: Thirty-six subjects were recruited to the depression group, schizophrenia group, and normal control (NC) group then were performed the Digit Symbol Test (DST), Digit Span Test (DSPT), and Verbal Fluency Test (VFT) to explore the characteristics of cognitive impairment and analyze its influencing factors. Results: Between the 3 groups, age, gender, and education showed no significant difference (P>0.05). Compared with the NC group, both depression and schizophrenia groups showed increased HAMD and HAMA scores，and this increase was more significant in the depression group (P<0.05); depression and schizophrenia groups also showed decreased DST, DSPT, and VFT scores, and this decrease was more apparent in the schizophrenia group (P<0.01). In all subjects, the DST, DSPT (backward recall), and VFT scores were positively correlated with education level, and the DSPT (forward recall) score was negatively correlated with age. In the depression group, the DST and DSPT (forward) scores were negatively correlated with HAMD scores, and the DSPT (forward) score was also negatively correlated with duration of illness (P<0.05). In the schizophrenia group, the DST score was negatively correlated with positive PANSS scores and duration of illness; the DSPT (backward) score was negatively correlated with duration of illness；the VFT score was negatively correlated with negative PANSS scores and duration of illness (P<0.05). Conclusion: Cognitive impairment is present in depression and schizophrenia patients at different levels. Compared with depressive symptoms, psychotic symptoms lead to more serious cognitive impairment. Cognitive impairment in depression patients more often affect thinking sensitivity and attention speed while in schizophrenia patients, it more often affects executive function and information extraction and processing.