Objective To investigate the characteristics of auditory P300 amplitude and latency and cognition in patients with clinical high-risk of psychosis (CHR). Method Thirty six CHR (study group) and thirty five healthy con?trols (control group) were included. Oddball paradigm and MATRICS Consensus Cognitive Battery (MCCB) were used to record auditory P300 and to evaluate the cognition, respectively. The structured interview for psychosis-risk syndromes (SIPS) was used to evaluate the clinic symptoms of patients. Result The cognition of CHR was significantly lower than healthy controls in information processing, attention/vigilance, working memory, verbal learning, visual learning, reason?ing and problem solving and social cognition (P<0.01). The study group showed decreased amplitude in Fz, Cz and Pz and delayed latency in Pz (P<0.05). P300 latency of CHR in Fz positively correlated with positive score of SOPS (r=0.544, P=0.001), while P300 amplitude positively correlated with verbal fluency (r=0.339,P=0.043). Conclusion Cogni?tion and P300 is abnormal in CHR. The correlation between P300 and clinical symptoms, cognitive dysfunction reminds that we should put more attention on the role of P300 in CHR subjects.