Public art is increasingly recognised for its pedagogical value, especially in higher education, where it enhances institutions' educational outcomes and expands students' learning experiences. However, its potential in basic education remains under-exploited. This study aims to bridge the gap by investigating how public art is effectively integrated into school curriculums and the educational benefits it offers students in their learning journey. Researchers, therefore, designed a student-centred public art intervention project, Dreams and Hopes, at a Chinese nonprofit primary school incorporating the school's educational goals. The project recruited 5th and 6th graders to create a giant mosaic mural for the campus' public space during the school's club and regular curriculum. To determine the educational benefits of the public art practice, researchers collected qualitative data using ethnographic methods in the project. The results showed that students at different stages (design, making, exhibition) gained competencies in three key themes: creativity (divergence, convergence, expression), practical ability (operation, innovation, collaboration), and self-identity (satisfaction, achievement, confidence). These competencies align with the school's educational goals and enhance students' learning experience. Problem-based guidance, a relaxed and enjoyable atmosphere, effective communication and a connection to reality are essential to these critical competencies. The study reveals that public art may support educational goals and benefit students. It also enhances the practical experience of public art in basic education and provides a model of intervention to educators. The study recommends that schools actively collaborate with external resources, emphasise the art practice's educational value, and provide platforms for student arts participation.