BackgroundSuicidal ideation serves as a sensitive predictive indicator for non-suicidal self-injury （NSSI） behavior， and NSSI behavior brings profound effects to both mental and physical health of senior high school students. Existing studies have made exploration on the relationship among insomnia， anxiety and NSSI behavior in the general population， but the internal mechanism of NSSI behavior in senior high school students with suicidal ideation requires further study. ObjectiveTo explore the pathway of anxiety between insomnia and NSSI behavior in senior high school students， so as to provide references for the intervention on NSSI behavior in such demographic. MethodsFrom December 10 to 15， 2021， cluster sampling was adopted to select 2 572 senior high school students across three senior high schools in Hubei Province as the research objects. Assessment was conducted by using Insomnia Severity Index （ISI）， Generalized Anxiety Disorder Scale-7 item （GAD-7） and Adolescents Self-Harm Scale. Spearman correlation analysis was conducted to examine the correlation among scores of scales finished by senior high school students with suicidal ideation. Model 4 from the SPSS 20.0 Process 4.2 was employed to test the mediating path of anxiety between insomnia and NSSI behavior. ResultsA total of 2 421 valid questionnaires （94.13%） were recovered， which revealed 554 cases （22.88%） with suicidal ideation and 408 cases （16.85%） with NSSI behavior. The scores of ISI， GAD-7 and Adolescents Self-Harm Scale of senior high school students with suicidal ideation were higher than those of students without suicidal ideation （Z=17.124， 20.611， 21.314， P<0.01）. As correlation analysis showed， the ISI score of senior high school students with suicidal ideation was positively correlated with scores of GAD-7 and Adolescents Self-Harm Scale （r=0.646， 0.354， P<0.01）， and GAD-7 score was positively correlated with the score of Adolescents Self-Harm Scale （r=0.375， P<0.01）. Among senior high school students with suicide ideation， anxiety acted in a mediating role between insomnia and NSSI behavior， with effect value of 0.111 （95% CI： 0.053~0.185）， accounting for 53.88% of the total effect. ConclusionInsomnia of senior high school students with suicidal ideation can not only directly affect NSSI behavior， but also indirectly affect NSSI behavior through anxiety. ［Funded by Research Project of Jingzhou Science and Technology Innovation Think Tank in 2022 （number， JZCXZK202209）］