Abstract: Traditional methods of mathematical expression retrieval mainly focus on the two-dimensional structure of expressions. It is difficult to retrieve mathematical expressions with the same semantics but different structures. Aimed at this problem, a mathematical expression query expansion method based on dependency parsing is designed. Based on the retrieval method of formula description structure (FDS) analytical expression structure information, the semantic words in the text surrounding the expression were extracted through the dependency syntax, and the index between operators, expressions, and semantic words was established. Through the second query of the semantic words, the purpose of retrieving mathematical expressions with the same semantics but different structures was realized. The experimental results show that dependency analysis can effectively extract the semantic words of mathematical expressions, and the semantic expression retrieval method is added at the same time, and the recall rate and precision rate are improved to a certain extent.