Abstract： Objective： To observe the effect of Qingkailing injection combined with diazepam on sleep quality and monoamine neurotransmitter of patients with insomnia. Methods： A total of 158 cases of patients with insomnia were selected and divided into the control group and the experiment group according to the random number table method ， 79 cases in each group. The control group was treated with diazepam， and the experiment group was treated with Qingkailing injection combined with diazepam. Both groups were treated for one month. Clinical effect and adverse reactions were observed in the two groups. Before and after treatment，score of Pittsburgh Sleep Quality Index(PSQI)，score of Mini- Mental State Examination(MMSE)， polysomnography parameters(sleep onset latency， total sleep time， sleep efficiency， wake after sleep onset)，as well as levels of 5- hydroxyindoleacetic acid(5- HIAA)，γ- aminobutyric acid(GABA)，dopamine (DA)，T lymphocyte subsets(CD4+/CD8+，CD4+，CD3+，CD8+ ) levels were observed in the two groups. Results：The total effective rate was 88.61% in the experiment group， higher than that of 75.95% in the control group(P＜0.05). When compared with those in the same group before treatment，PSQI scores and levels of serum CD8 + in the two groups were decreased after treatment(P＜0.05)， sleep onset latency and wake after sleep onset shortened(P＜0.05)， total sleep time prolonged(P＜0.05)，sleep efficiency as well as scores of MMSE and levels of 5- HIAA，GABA，DA，CD4 +，CD3 +，and CD4+/CD8+ in serum increased(P＜0.05). After treatment， when compared with those in the control group， PSQI scores and levels of serum CD8 + were lower in the experiment group(P＜0.05)， sleep onset latency and wake after sleep onset shorter(P＜0.05)，total sleep time longer(P＜0.05)，sleep efficiency as well as MMSE scores and levels of 5-HIAA，GABA， DA， CD4 + ， CD3 + ， and CD4 +/CD8 + in serum higher(P＜0.05). There was no significant difference being found in the comparison of incidence of adverse reactions between the two groups(P＞0.05). Conclusion： The therapy of Qingkailing injection combined with diazepam has a significant clinical effect in the treatment of insomnia. It can significantly regulate levels of monoamine neurotransmitter and T lymphocyte subsets；thus，the sleep quality can be effectively improved，sleep time prolonged，and cognitive function enhanced，with good safety.