Background: Suicidal ideation in children has received less attention than in adolescents. This study aimed to explore the self-reported prevalence of suicidal ideation among children aged 6-12 and to identify the relationship between self-reported suicidal ideation and children's mental health reported by different informants in Chinese setting. Method: The study sample was 1479 children aged 6-12 from three elementary schools in Tianjin. Children completed the Dominic Interactive to report their mental health and suicidal ideation. Parents and teachers completed the Socio-Demographic Questionnaire and the Strengths and Difficulties Questionnaire (SDQ). Results: The prevalence of suicidal thoughts and death thoughts was 18.05 % and 16.90 %, respectively. Parent reported emotional symptoms, ADHD, and externalized problems were associated with death thoughts, and ADHD was associated with suicidal thoughts. For teacher's reports, emotional symptoms, and impact were associated with death thoughts, and ADHD, peer problems, internalized problems, and internalized and externalized comorbidity were associated with suicidal thoughts. All of the children's self-reported mental health problems were associated with suicidal thoughts and death thoughts. Limitations: Causality cannot be inferred in a cross-sectional study. Conclusion: Suicidal ideation is not uncommon in Chinese children. The relationships between mental health problems and suicidal ideation varied in different informants. Suicide prevention in young children should be enhanced, and screening for suicidal ideation is recommended at the onset of different informants who reported specific mental health problems.