Objective To explore the relationship between parental marital adjustment and adolescent depressive symptoms， as well as the mediating role of maternal depressive symptoms. Methods From November to December 2021， students and their mothers from a high school in Henan Province were selected as the research subject. The parental marital adaptation and adolescent depressive symptoms were investigated with the Locke-Wallace Marital Adjustment Test （LW） and Children's Depression Inventory （CDI）， and the maternal depressive symptoms were investigated with the Center for Epidemiologic Studies Depression Scale （CES-D）. Spearman correlation was used to analyze the correlation among adolescent depressive symptoms， parental marital adjustment， and maternal depressive symptoms. This study conducted the mediating effect test using the Process 3.3 plugin in SPSS. Results This study obtained 1 039 valid matching questionnaires. The LW score and CDI score of 1 039 adolescents were ［84（71，95）］ and ［13（8，18）］， respectively， while the CES-D score of 1 039 adolescent mothers was ［3（0，12）］. 21.56% （224/1 039） of adolescents had a CDI score of ≥ 19， and 20.31% （211/1 039） of mothers had a CES-D score of ≥ 16. Correlation analysis showed that there was a negative correlation between parental marital adjustment and adolescent depressive symptoms， as well as maternal depressive symptoms （r=-0.10， -0.48； P＜ 0.01）， and maternal depressive symptoms were positively correlated with adolescent depressive symptoms （r=0.12， P ＜ 0.01）， with statistically significant differences. The mediating effect of maternal depressive symptoms between parental marital adjustment and adolescent depressive symptoms was significant ［95%CI （-0.031， -0.004）］， with an effect value of -0.017， accounting for 51.43% of the total effect. Conclusions Parental marital maladjustment can increase the risk of depression in adolescents by increasing maternal depressive symptoms. Attention should be paid to the impact of marital relationships and family environment on the emotions of adolescents.