Crop pests and diseases are important limiting factors that restrict agricultural development and cause crop yield reduction and quality decline. Constructing knowledge graphs to reasonably integrate crop pest and disease data, solving crop pest and disease problems encountered in agricultural production through question-andanswer methods, and providing scientific and reasonable pest and disease prevention knowledge are of great significance for realizing agricultural informatization. This paper aims to summarize the current application status of agricultural knowledge graphs in the field of crop pests and diseases, the current status of the construction of related question-and-answer systems, and key technologies, and summarize the existing problems; by constructing pest and disease knowledge graphs and question-and-answer systems for empirical analysis and visualization, the design of the crop pest and disease question-and-answer framework, natural language understanding configuration and data construction, dialogue management design, knowledge graph query, and prototype system display are completed,and multi-round question-and-answer of crop pests and diseases is realized. The existing problems are analyzed and the future development direction of the crop pest and disease question-and-answer system is prospected, providing a reference for the construction of related knowledge graphs and question-and-answer systems.