This paper conducts a literature review to examine domestic and international research on symbolic literacy, defining a four-tiered structure of symbol awareness: perception, operation, reasoning, and representation. It analyzes the differentiated impact of each tier on algebra learning in junior and senior high schools, and constructs a tiered algebra teaching system that integrates secondary education. The study points out that existing research suffers from incomplete coverage of educational stages, a lack of assessment tools, and weak empirical evidence in teaching. It proposes future research directions such as longitudinal tracking, tiered teaching experiments, and digital integration, providing a reference for cultivating symbolic literacy in secondary schools.