Firstly, this study summarized the current research status of the domain knowledge graph. Secondly, the development trend of the domain knowledge graph was introduced. Then, this study sorted out some difficulties in the construction of water conservancy knowledge graph, proposed a research framework including main modules such as knowledge representation, extraction, fusion, reasoning, and storage, and briefly summarized the research content of each module. Finally, the construction of domain knowledge graph encountered some problems, such as the single representation, the extraction sample sparse, the multisource knowledge conflict, the rule representation difficulty, and the inefficient data management. Therefore, the rationalized representation, accurate and comprehensive extraction, realtime fusion, interpretable reasoning, and highperformance storage are regarded as the next research direction of water conservancy knowledge graph.