Objective To explore the mediating effect of parental hostile attribution bias on depression and anxiety be-tween parents and children,so as to provide the reference for the promotion of children's mental health.Methods Stu-dents of grades 2-6 in two public primary schools in Linping District,Hangzhou City and their parents were investigat-ed using stratified sampling method in November 2022.Emotions of children were surveyed using Depression Self-Rat-ing Scale for Child(DSRSC)and Screen for Child Anxiety Related Emotional Disorders(SCARED),while emotions and hostile attribution bias of parents were surveyed using Self-rating Depression Scale(SDS),Self-rating Anxiety Scale(SAS)and Social Cognitive Screening Questionnaire(SCSQ).Mediating effect of parental hostile attribution bias on de-pression and anxiety between parents and children was analyzed using a structural equation model.Results Totally 300 questionnaires were allocated,and 263 valid questionnaires were recovered,with an effective rate of 87.67%.There were 137 boys(52.09%),and 126 girls(47.91%),with a mean age of(9.95±1.44)years.There were 69 fathers and 194 mothers investigated.The prevalence of depression among parents was 27.00%,the prevalence of anxiety among par-ents was 4.18%,and the median score of hostile attribution bias was 1.00(interquartile range,2.00).The prevalence of depression among children was 11.03%,and the prevalence of anxiety among children was 29.66%.Parents'depression and anxiety affected children's depression and anxiety directly(effect value=0.270,95%CI:0.131-0.436),and also indi-rectly affected children's depression and anxiety by increasing their hostile attribution bias(effect value=0.028,95%CI:0.004-0.082),with the mediating effect contributed 9.40%of the total effect.Conclusion Parents'depression and anxi-ety affect children's depression and anxiety directly or indirectly through hostile attribution bias.