Recently, Social-Emotional Learning (SEL) has become a prevailing educational trajectory globally, while relationship skills are one of the five disciplines, which refers to “the ability to establish and maintain healthy and supportive relationships and to effectively navigate settings with diverse individuals and groups.” (Collaborative for Academic, Social, and Emotional Learning, n.d.) It can facilitate healthy and supportive student relationships, such as supporting effective communication, actively listening to others and collaborating in problem-solving. Evan S. Tobias (2013) mentioned that applying participatory culture in school music programs by encouraging youngsters to create their own compositions is needed if we look forward to a connection beyond school music classroom settings.　　Hence, this study aims to integrate the relationship skills into music composition group activities in school music classes. This study adopted the case study method, which consisted of forty-one eighth-graders in Taipei City. This project lasted for six lessons, with approximately thirty minutes each lesson. Students were divided into six groups, with five to six students in each group. Each group was required to record environmental sounds in their daily lives. Subsequently, the students discussed the style and chose the elements to compose music as a group. These unique compositions incorporated the daily sounds from Taipei City by using BandLab Ⓡ. Students recorded their reflections on relationship skills using researcher-designed worksheets for each lesson. Researchers also analysed students’ interactions in class using the researcher-designed observation form. Associated with the above worksheets and observation forms, researchers studied the possibility of integrating interpersonal relationship skills in school music lessons. 　　The purposes of this study are: 1) to develop an interdisciplinary approach to music classes for eighth graders through composing using digital musical software to promote compositional-oriented learning in the school music curriculum; 2) to cultivate their abilities in relationship skills such as communication, teamwork skills, and task allocation, and refine their team-based learning experiences, through group activities while teaching; 3) to present suggestions regarding the lesson plans incorporating SEL into school music education, as a reference for future case studies and research.　　Based on the results, many suggestions will be discussed: 1) the ideas for teachers to incorporate relationship skills into the lesson plans of the school music curriculum; 2) the application of digital musical software to enhance students’ collaboration and communication; 3) the ways for teachers to foster an experiential and meaningful learning experience using compositional-oriented learning in the school music curriculum.