BACKGROUND Since December 2019, an unexplained pneumonia has broken out in Wuhan, Hubei Province, China. In order to prevent the rapid spread of this disease, quarantine or lockdown measures were taken by Chinese government. These measures turned out to be effective in containing the contagious disease. Quarantine itself, however, would potentially cause certain health risks among the affected population, such as sleep disorder. OBJECTIVE The aims of this work were to analyze the volume of insomnia-related search during the COVID-19 outbreak in China, to explore the potential use of the Baidu Index for monitoring social and psychological distress, and to help community health workers provide timely and effective interventions for the public. METHODS In the context of the pandemic, we conducted a descriptive analysis of the overall search situation. Spearman's correlation analysis was used to explore the relationship between daily search index values for insomnia-related terms and daily newly confirmed cases. The means of search volume for insomnia-related terms during the COVID-19 quarantine or knockdown period (January 23rd, 2020 to April 8th, 2020) were compared with the those during 2016 to 2019 using a Student's t test. Finally, by analyzing the overall daily mean of insomnia in various provinces, we further evaluated whether there existed regional differences in searching for insomnia during COVID-19 isolation. RESULTS During the COVID-19 period, search volume in each category had increased significantly, especially the “treatment” category. A significant positive correlation between daily newly confirmed cases and most of insomnia-related Baidu Index was identified. Compared with the same period in the past 4 years, a significant change in insomnia-related search volume was found with COVID-19 quarantine period. We also found that all provinces suffered from insomnia during the quarantine period, with Guangdong province representing the leading areas for insomnia-related search. CONCLUSIONS Quarantine measures have led to an increase in insomnia-related searches during the COVID-19 pandemic. Community medical staff should use big data-based tools to screen for insomnia and mental health problems. Early interventions toward insomnia and associated mental health are also essential for prevention and reduction of the long-term impact of the major traumatic events.