Abstract: Objective To study the efficacy and adverse reaction of Escitalopram in the treatment of primary insomnia. Methods Total 80 patients with sleep disorders in our hospital between June，2014 and June，2015 were enrolled and randomly divided into observation group and control group with 40 cases in each group.The observation group was given Escitalopram Oxalatetablets [After breakfast,oral,initial dose of 5 mg/d,gradually increased to 20 mg/d] and Zolpidem tablet[at bedtime,oral,initial dose of 5 to 10 mg/d] for 8 weeks,while the control group was given Zolpidem tablets [at bedtime,oral,initial doseof 5 to 10 mg/d] for 8 weeks.Before the treatment and 1,4 and 8 weeks after the treatment,Pittsburgh sleep quality index(PSQI) scale,patient health questionnaire (PHQ-9) index were measured,and the incidence of adverse reactions was observed.SPSS 18.0 was used to analyze the data. Results PAQI total score on the 1st,4th and 8th weekend after the treatment decreased in both groups，P<0.05.On the 8th weekend,the total scores of PSQI in the observation group were significantly lower than that in the control group,P<0.05.PHQ-9 total scoreon the 1st,4th and 8th weekend after the treatment decreased in both groups，P<0.05.On the 8th weekend,the total scores of PHQ-9 in the observation group were significantly lower than that in the control group,P<0.05.The mild adverse reactions were found in both groups.The incidence of adverse reactions in the observation group was 32.5%,and in the control group was 27.5%,the difference was not statistically significant，P>0.05. Conclusion Escitalopram can effectively improve the sleep quality in patients with primary insomnia,but the incidence of adverse reactions such as tremor and constipationis relatively high,which should be paid more attentions.