Objective To investigate the cognitive function in patients with depressive disorder in remission. Methods A total of 130 depressive patients， who were first diagnosed in the General Hospital of Shenyang Military Region from January 2017 to July 2017， and 100 healthy controls were selected as the research subjects. The Hamilton Depression Scale（ HAMD） was used to evaluate the severity of patients. The Wisconsin Card Sorting Test， Stroop Color-Word Test， Trail Making Test， Verbal Fluency Test and Wechsler Memory Scale were used to evaluate information processing speed， word fluency， working memory， cognitive flexibility， link memory， and logical memory of all subjects. Escitalopram Oxalate tablets was used to treat patients. Depressed mood and cognitive function of patients were assessed before treatment and 6 months after. Results Finally 87 cases of the depression group and 69 of the control group were recruited in this research. Before treatment， the cognitive function in depression group was significantly lower than that in healthy control group， with statistical significance（ P ＜ 0.05）. After 6 months of treatment， according to the standard of DSM-5， 75 depressive disorder patients have met the criteria of remission. After 6 months of treatment， the HAMD score of depressive disorder patients decreased from（ 34.52±5.01） to（ 5.01±2.98）， and the difference was statistically significant（ F=23.132， P ＜ 0.05）. However there was no significant difference between the depression groups and the healthy control group（ P=0.689）. After 6 months of treatment， cognitive functions （working memory， cognitive flexibility， connection memory and logical memory instantly / delayed） improved significantly except for information processing speed and word fluency in depressive disorder patients（ P＜0.05）. Conclusions Cognitive impairment（ information processing speed， word fluency， working memory， cognitive flexibility， connection memory and logical memory immediate / delayed） occurs during the onset of depressive disorder. During the remission period， other cognitive functions were significantly improved besides information processing speed and word fluency. The results shows that information processing speed and word fluency were probably the phenotypes of depressive disorder， while other cognitive factors may be state types.