Objective To discuss the difference of cognitive function in patients of first-episode schizophrenia with and without metabolic syndrome.Methods Event related potential detection and Wechsler Memory Scale (WMS) was determined in 57 patients of first-episode schizophrenia with metabolic syndrome (research group) and 57 patients of first-episode schizophrenia without metabolic syndrome (control group),and the psychiatric symptom in two groups was assessed by the application of the positive and negative symptoms scale (PANSS).Results The memory quotient score was (78.51 ± 12.54) scores in research group,and (92.01 ± 17.49) scores in control group,and there was significant difference between two groups (t =-2.130,P=0.047).The short-term memory,instantaneous memory impairment in research group were lower than those in control group(t =2.151-3.054,P=0.007-0.046).The latency of P300 was (325.10 ±22.46) ms in research group and (284.60 ±22.46) ms in control group,and there was significant difference (t =3.454,P =0.003).The amplitude was (6.56 ± 1.61) μ V in research group and (9.78 ±1.73) μV in control group,and there was significant difference (t =-4.307,P =0.000).Conclusion The patients of first-episode schizophrenia with metabolism syndrome has more severe cognitive impairment than those without metabolism syndrome.