Protein-protein interaction (PPI) plays an important role in understanding biological processes. In order to resolve the noise interference brought by appositive dependency, an improved tree kernel-based PPI extraction method was proposed. Some relevant processing rules were defined to effectively optimize the shortest dependency path between two proteins. On this basis of these rules, an effectively optimized path was used to direct the cutting of constituent parse tree, which made the constituent parse tree for PPI extraction more precise and concise. The experimental results show that our e...