Background.　Non-suicidal　self-injury　(NSSI),　of　which　the　predisposing　factors　are　complex　and　diverse,　profoundly　affects　the　physical　and　mental　health　of　young　people.　Therefore,　this　work　established　an　NSSI　intermediary　network　model　considering　the　interaction　of　multiple　factors.　A　mediating　effect　between　attentiondeficit/hyperactivity　disorder　(ADHD)　and　NSSI,　considering　the　influence　of　comorbidities,　such　as　depression,　anxiety,　and　impulsive　personality,　was　proposed　based　on　sex　differences.　Methods.　A　total　of　2,689　middle　school　students　in　Ningbo　City,　Zhejiang　Province,　China,　were　randomly　sampled　and　participated　in　this　study.　Data　regarding　their　demographic　characteristics,　attention　deficit,　hyperactivity/impulsivity,　NSSI,　anxiety,　depression,　internet　addiction,　and　other　comorbid　symptoms　were　collected　and　analyzed.　After　initially　screening　the　data,　variables　were　assessed　for　significance　using　a　single-factor　inter-group　difference　analytic　method,　and　a　binary　logistic　regression　analysis　was　performed.　The　intermediary　effect　of　factors　influencing　NSSI　in　males　and　females　was　also　analyzed.　Results.　The　overall　NSSI　rate　was　15.16%.　The　results　showed　that　the　impact　of　individual　impulsivity　characteristics　(impulsiveness,　the　ADHD　with　hyperactivity/impulsivity　subtype)　on　NSSI　behavior　was　not　significant　(regression　results,　P　＞　0.05).　The　degree　of　association　between　ADHD　with　attention　deficit　and　ADHD　with　comprehension　deficit　subtypes,　and　other　comorbid　symptoms　(depression,　anxiety,　and　internet　addiction　disorder)　and　NSSI,　with　odds　ratios　(ORs)　of　7.6/6.42/436.68/3.82/1.86,　and　95%　bootstrap　confidence　intervals　(CIs)　of　4.64,　12.87/3.46,　12.67/137.42,　2659.13/2.32,　6.37/1.31,　2.82,　respectively.　The　results　also　showed　significant　effects　of　ADHD　subtypes　on　comorbid　symptoms　and　the　path　effects　of　NSSI　(P　＜　0.01).　Among　them,　the　mediating　effect　was　the　strongest　when　anxiety　was　the　mediating　variable,　and　the　mediating　effect　of　girls　was　higher　than　that　of　boys.　Conclusion.　The　results　of　this　work　demonstrated　the　influence　of　ADHD　symptoms　on　NSSI　behavior.　Among　patients　with　ADHD,　patients　with　subtypes　with　obvious　attention　deficit　characteristics　were　more　likely　to　exhibit　NSSI　behavior,　whereas　the　hyperactive　impulse　subtype　had　no　direct　impact　on　NSSI.　We　conclude　that　adolescent　impulsivity　may　not　be　directly　related　to　NSSI　behavior　and　that　impulsive　characteristics　jointly　affect　NSSI　behavior　through　a　series　of　NSSI　comorbid　symptoms.　Notably,　the　probability　of　symptom　onset　and　the　degree　of　comorbidity　was　significantly　higher　in　girls　than　in　boys　of　the　same　age,　and　girls　were　more　prone　to　NSSI　behavior.　These　findings　provide　effective　theoretical　support　for　the　prevention　and　treatment　of　adolescent　NSSI　behavior.