Abstract: Objective To explore the differences of cognitive functions in the patients with chronic insomnia disorder(CID) in the different subtypes and the correlations between cognition and objective sleep parameters. Methods Ninety-five patients with CID were diagnosed in sleep and memory disorders outpatient clinic from August 2012 to February 2014.Then patients were divided into the group of patients with difficulty initiating sleep(14 patients),patients with early morning awakening(EMA,24 patients),patients with difficulty maintaining sleep(24 patients) and patients with mixed symptoms (MS,33 patients) in accordance with complaints.The sleep profile was measured using one-night polysomnogram.On the next morning,the sleep quality,cognitive function and depressive state were evaluated using Pittsburgh Sleep Quality Index(PSQI),Montreal Cognitive Assessment Scale(MoCA) and Hamilton Depression Scale(HAMD),respectively. Results The subscale scores of MoCA in the attention(H=10.94,P_s<0.05) and delayed recall(H=22.79,P_s<0.001)were significantly different among the 4 subtypes of patients,i.e.,the EMA and MS groups had lower scores compared to the other two groups (P_s<0.05).Moreover,the scores in the subscales of visual-spatial and executive function and language positively correlated with the N3 duration(r=0.245,0.219;P_s<0.05) and N3 in sleep period time (r=0.234,0.222;P_s<0.05);the scores in attention subscale positively correlated with the N2 duration and N2 in sleep period time(r=0.209,0.364,P_s<0.05);and the scores in delayed recall subscale positively correlated with the N2 duration and N2 in sleep period time(r=0.218,0.290;P_s<0.05),and N3 duration and N3 in sleep period time (r=0.335,0.343;P_s<0.05). Conclusion The cognitive functions had discrepancies among the patients with different subtypes of CID,and visual-spatial and executive function,attention subscale and delayed recall subscale might be associated with objective parameters of NREM sleep in the CID sufferers.