Previous studies have proposed that the grammars may serve as a rule-based scaffolding to facilitate story comprehension in storytelling activities. Such scaffoldings may inform students of crucial story elements and possible transitions among different elements. However, how these scaffoldings may influence story creation/writing activities is still not very clear. This study aims to understand and explore the relationship among rule-based scaffoldings, creative self-efficacy and storytelling products. By gathering the stories developed by 53 sixth graders and their creative self-efficacy in a quasi-experiment setting, this study investigated whether providing these rule-based scaffoldings may influence their performance and creative self-efficacy. The results of this study indicated that with these rule-based scaffoldings, students produced better storytelling products in terms of content quality. However, the presence of story grammar rules also limited the students' freedom of creative thinking, and thus reduced the creative self-efficacy level at the early stage of learning to create stories. Such findings support that the rule-based scaffolding may be more helpful in facilitating storytelling in the idea exploration phase than in the generation phase. Educators may need to be cautious regarding the time point at which rule-based scaffoldings would be most effectively integrated with learning activities.