Adolescent　mental　health　problems　are　becoming　increasingly　prevalent　and　concerning.　This　study　aimed　to　evaluate　the　effectiveness　of　a　school-based　music　intervention　program　in　improving　the　mental　health　of　middle　school　students.　From　September　2023　to　January　2024,　a　class-based　stratified　randomized　controlled　trial　was　conducted　at　a　rural　middle　school　in　Nanping　City,　Fujian　Province,　China.　Seventh-　and　tenth-grade　students　were　recruited　and　randomly　assigned　to　either　an　intervention　group　or　a　control　group.　The　intervention　group　participated　in　a　17-week　structured　music　program,　while　the　control　group　continued　with　regular　school　activities　without　additional　intervention.　Mental　health　status　was　assessed　using　the　Depression　Anxiety　Stress　Scale　for　Youth　(DASS-Y).　A　total　of　414　students　(mean　age:　14.57　+/-　1.53　years)　were　included.　Baseline　sociodemographic　characteristics　were　similar　between　groups,　although　students　in　the　control　group　were　slightly　more　likely　to　report　enjoying　school　(p　=　0.029).　Post-intervention,　the　intervention　group　showed　significant　reductions　in　the　detection　rates　of　depression　(13.14%　to　1.71%),　anxiety　(14.29%　to　5.14%),　stress　(5.17%　to　0.00%),　and　overall　mental　health　problems　(18.29%　to　5.71%)　(all　p　＜　0.001),　while　no　significant　changes　were　observed　in　the　control　group　(all　p　＞　0.05).　Between-group　comparisons　at　post-intervention　further　revealed　significantly　lower　rates　of　depression　(1.71%　vs.　7.53%),　anxiety　(5.14%　vs.　12.13%),　stress　(0.00%　vs.　4.06%),　and　overall　mental　health　problems　(5.71%　vs.　14.64%)　in　the　intervention　group.　These　findings　suggest　that　school-based　music　intervention　programs　may　be　an　effective　and　scalable　approach　to　promoting　adolescent　mental　health.　Further　research　is　needed　to　explore　their　long-term　impact　and　broader　applicability.