The aim of this study was to investigate the characteristics of cognitive function damage in chronic schizophrenia patients with metabolic syndrome (MS); 388 patients were divided into two groups: MS group (180 people with schizophrenia and MS) and non-MS group (208 people with schizophrenia but without MS). The Positive and Negative Syndrome Scale (PANSS) and the Treatment Emergent Symptom Scale (TESS) were used to evaluate clinical symptoms and drug adverse reaction. The Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) was used to assess cognitive function. There was no significant change in PANSS (p = 0.53) and TESS score (p = 0.26) between the MS group and the non-MS group. However, RBANS total scale score as well as attention, immediate memory, and delayed memory scores in the MS group were significantly lower than those in the non-MS group (p < 0.05). There was no significant change in visuospatial skill (p = 0.07) and language scores (p = 0.08) between the two groups. Besides, course of disease, triglyceride, antipsychotic drug type, systolic pressure, negative symptom factor, and education level showed a notable significance for cognitive function damage in turn. MS might aggravate injury of cognitive function in chronic schizophrenia, especially in immediate memory, delayed memory, and attention.