Objective <p>Isolation in Fangcang shelter hospitals during Shanghai lockdown may exacerbate mental health problems or even suicide risk. This study aimed to examine the mediating effects of anxiety and depression in the relationship between insomnia and suicidal ideation.</p> Methods <p>Participants were recruited via convenience sampling method. A total of 461 individuals completed the cross-sectional assessments, which was designed to measure demographic information, Insomnia, anxiety, depression, and suicidal ideation.</p> Results <p>All variables of interest were positive and significant associated with each other (all <i>P</i> &lt; 0.01). Anxiety fully mediated role between insomnia and suicidal ideation, accounting for 62.65% of the total effect. Similarly, depression also acted as a fully mediator in this relationship, with a mediating effect of 77.11%.</p> Conclusion <p>Insomnia was associated with an increased risk of suicidal ideation, with anxiety and depression serving as full mediators in this relationship. Targeted interventions addressing insomnia, anxiety, and depressive symptoms should be implemented to mitigate and potentially prevent suicidal ideation among isolated individuals.</p>