Background: Insomnia is a more and more common sleep disorder, which affects health and quality of life. Aromatherapy is one of the effective treatments to improve sleep quality. This paper is to comprehensively evaluate the existing research on aromatherapy as a treatment of insomnia to verify its therapeutic effect. Results: 16 studies (19 comparisons) met inclusion and exclusion criteria were used for meta-analysis. The results showed that aromatherapy had a significant effect on improving sleep quality (WMD: -2.52; 95% CI: -3.24 to -1.79). Subgroup analysis showed that different types of patients from different countries can improve their sleep quality through aromatherapy. The inhalation group, rather than the massage group had an obvious therapeutic effect, which may be due to the number of studies using massage included in our analysis is too small. What's more, different intervention duration does not seem to have a significant effect on the efficacy of aromatherapy. Conclusion: Aromatherapy has a significant effect on improving sleep quality. It can be used as one of the non-pharmacological treatments for insomnia, and relevant guide should be formulated to facilitate future clinical applications.