Objective To construct a nursing evidence dataset,develop a generative artificial intelligence-based nursing evidence question-answering model,and evaluate its usability,with the aim of providing real-time decision support for clinical nurses. Methods Domestic and international nursing literature was comprehensively retrieved and classified according to the “5S” evidence pyramid. A training dataset was constructed,comprising more than 6,000 evidence summaries,over 15,000 guidelines and expert consensuses,and more than 500,000 systematic reviews. A domestically developed open-source large language model with strong performance was selected as the base model. Based on the training dataset,over 800,000 instruction fine-tuning sample pairs and more than 700,000 nursing evidence were generated. Supervised fine-tuning and retrieval-augmented generation were employed to train and develop a nursing evidence question-answering model. In September 2025,23 clinical nurses were recruited via convenience sampling to test the model. The usability of the model was evaluated using a self-developed model usability evaluation questionnaire. A lower score indicates better usability. Results All 23 nurses completed the model trial. In the model usability evaluation questionnaire,the scores were as follows:model quality dimension(1.99±0.85) points,information quality dimension(2.59±1.03) points,interface quality dimension(2.28±1.25) points,user satisfaction dimension(2.76±1.00) points,intention to use dimension(2.19±1.32) points,and net benefits dimension(2.03±0.78) points. Conclusion The overall usability of the nursing evidence question-answering model was good,and its use may help clinical nurses obtain evidence-based nursing information more efficiently. Future work could further expand the model’s functions and enrich the output information.