In the current information environment, unstructured text is an important part of information. How to quickly extract the required information from text data and provide users with an efficient way to acquire information has become an urgent problem to be solved in the current information service field. Based on semantic retrieval and an extraction-type document reading comprehension model, this work studies how to effectively extract required answers from large document libraries according to users’ questions and constructs an information service question answering system based on document libraries. In the current environment with massive information, it is of great significance to improve the efficiency of users’ information acquisition. Experiments show that the system can quickly and accurately locate the answers to the users’ questions and help them get the required information rapidly.