This study aimed to estimate the prevalence of adverse childhood experiences (ACEs) and explore their associations with mental health among Chinese adults. This population-based, cross-sectional survey was conducted in China in 2023. Data on participants' ACEs, depressive symptoms, anxiety symptoms, suicidal ideation, and other information were collected among participants who were selected using multi-stage stratified quota random sampling. Of 30,054 participants, 26.0% (7809/30,054) reported at least one ACE. The prevalence of major depression symptoms, moderate or severe anxiety symptoms, and suicidal ideation were 19.5%, 12.7%, and 21.7%, respectively. There was a dose‒response relationship between the cumulative number of ACEs and mental health among Chinese adults. Compared to those with no ACEs, the adjusted odds ratios (ORs) and 95% confidence interval for major depression symptoms were 1 ACE: 1.340 (1.226‒1.465), 2 ACEs: 1.769 (1.588‒1.971), 3 ACEs: 2.172 (1.909‒2.472), and ≥4 ACEs: 3.084 (2.712‒3.507). The ORs for anxiety symptoms of 1, 2, 3, and ≥4 ACEs were 1.262 (1.135‒1.403), 1.714 (1.513‒1.942), 2.119 (1.831‒2.452), and 2.890 (2.512‒3.325). The ORs for suicidal ideation were 1.056 (0.966‒1.154), 1.324 (1.188‒1.477), 1.470 (1.287‒1.679), and 3.134 (2.761‒3.557). Sexual abuse survivors were at great risk for mental health problems. Comprehensive measures are needed to support populations affected by ACEs.