School uniforms are a non-autonomous self-performance of students in public high schools under the disciplinary power of the school. Previous studies have mostly focused on students' resistance to uniforms as reflected in symbolic interactionism and subcultural construction. However, these studies have prompted some reflections: Are the uniform systems in today's public high schools as strict as the public imagines? Have they changed with the times? Is there a potential connection between uniform systems and public recognition of schools? Do high school students still commonly modify or resist uniforms? How do they perform self-expression and seek self-identity? Moreover, previous researchers have not studied uniforms from the perspective of those who are disciplined by the uniform system, lacking long-term observation and personal experience. Drawing on my daily observations as a student at a key high school in Hangzhou and on semi-structured interviews with students from multiple schools, this study uses qualitative research methods to horizontally compare institutional heterogeneity in uniform styles, dress regulations, and inspection intensity among key high schools in Hangzhou. It also takes a key high school in Hangzhou as a field to explore the specific ways students there engage in self-performance. The findings are as follows: (1) The uniform policies of key high schools in Hangzhou are closely related to student quality, school culture, and academic performance. (2) With the changing times, most students do not resist the act of "wearing a uniform" itself; instead, they regard it as a natural given, reflecting the reshaping of subjectivity brought by the internalized discipline of the uniform system. (3) The reshaped subjectivity still yearns for self-identity. Students use residual performative spaces—such as earrings, shoes, and accessories—to maintain limited space for self-expression.