This study investigated the feasibility of using ChatGPT as a scaffold for grammar learning by conducting demonstrations and analyzing responses from three models: the basic model, TutorMe, and Grammar! The analysis revealed that the basic model employed inappropriate scaffolding strategies and displayed hallucinations regarding school grammar knowledge. The TutorMe model provided improved scaffolding responses but still exhibited inaccuracies in grammatical knowledge. The Grammar! model enhanced the accuracy of grammar knowledge through Retrieval-Augmented Generation; however, it showed limitations in its role as a scaffold by providing direct answers rather than guiding the learning process. To effectively utilize ChatGPT in grammar learning, developing AI training corpora that support scaffolding strategies and improve search-augmented generation capabilities based on school grammar problem-solving data.