Objective: To understand and compare the differences in help-seeking behavior among junior high school students and senior high school students and their association with non-suicidal self-injury to provide a basis for the prevention and control of non-suicidal self-injury among middle school students. Methods: Three middle schools in Nanchang were selected,and the survey were conducted among 4 434 students through the General Situation Questionnaire, the Ottawa Self-injury Judgment Entry, and the Middle School Students Help Seeking Behavior Questionnaire, and SPSS 22.0 was used for statistical analysis. Results: The NSSI detection rate among middle school students was 33.3% , and junior high school students detection rate(36.0%) were higher than high school students(29.6%) (χ 2=19.41，P<0.01). Differences in willingness to ask for help, asking for help from family and teachers, and talking face-to-face for help were statistically significant (all P<0.01) among NSSI participants and non-NSSI participants, for both junior high school and high school students. Females (OR=1.45), class cadres (OR=1.26), urban household registration (OR=1.45), frequent scolding by elders (OR=1.98) and a high academic burden (OR=1.39) all possible increased the risk of NSSI in junior high school students, while assistance to family members (OR=0.95) or teachers (OR=0.95) possible reduced the risk of NSSI in junior high school students. Females (OR=1.50), class cadres (OR=1.34), only children (OR=1.45), fathers with college education and above (compared to junior high school and below) (OR=1.56), frequent scolding by elders (OR=2.08), frequent corporal punishment from elders (OR=4.12) and high academic burden (OR=1.38) possibly increased the risk of NSSI among high school students, while willingness to ask for help (OR=0.82), asking for help from family (OR=0.95) and teachers (OR=0.96) possible reduced the risk of NSSI among high school students. Conclusion There are some differences in help-seeking behavior between junior and high school students, and school and parents should actively focus on middle school students help-seeking behavior and encourage them to seek help.