Objective:To investigate the efficacy and safety of internet-based cognitive behavioral therapy for insomnia(iCBT-I) combined with estazolam for patients with chronic insomnia.Methods:Patients with chronic insomnia were randomly assigned to treatment group which were intervened with iCBFI combined with estazolam( n=46) and control group which were intervened with estazolam ( n=43) for 8 weeks according to random number table.Pittsburgh sleep quality index (PSQI) and state-trait anxiety inventory (STAI) were used to measure the anxious state, anxious trait and sleep quality at three time points: before intervention(T1), after one month(T2) and two months(T3). Treatment emergent symptom scale (TESS), blood routine, urine routine, liver and renal function and electrocardiogram were used to measure the safety.The dosage of estazolam was compared between the two groups after two months.χ 2 test and repeated measurement analysis of variance were performed by SPSS 19.0. Results:The PSQI scores of control group and treatment group were (10.41±2.48) vs (9.98±2.96) at T2 and (9.97±2.13) vs (7.82±1.57) at T3.The state anxiety scores of control group and treatment group were (57.27±2.74) vs (56.27±2.89) at T2 and (45.67±2.62) vs (42.67±2.97) at T3.The data of T2 and T3 were statistically significant compared with those before intervention(all P<0.05). Compared with the control group, the treatment group was better on treatment efficiency(86.96% vs 69.77%) at T3( P<0.05). PSQI score, subjective sleep quality, sleep efficiency, sleep disorders, sleep drugs, daytime dysfunction, drug maintenance and adverse reaction were significantly different between the two groups at T3 ( P<0.05). Conclusions:Internet-based cognitive behavioral therapy combined estazolam for insomnia can improve sleep quality, anxious state and trait for chronic insomnia patients.Good safety was improved, as well as reducing the need of drug.So it's worthy of clinic application.