In the context of competency-based education reform, the integration of multimedia tools—particularly scenario-based videos—has emerged as a promising approach to enhance moral education in primary schools. This study investigates the design and pedagogical use of scenario-based videos in Grade 3 moral education through a process-oriented framework. Employing a mixed-methods design, data were collected from 301 primary school teachers via surveys and from an experimental intervention involving 70 Grade 3 students divided into control and experimental groups. The findings reveal that although 97.7% of teachers recognize the necessity of scenario-based videos, their classroom implementation remains inconsistent, primarily due to the lack of structured design guidance. In response, the study proposes a five-step design process: (1) identifying learning objectives, (2) constructing moral dilemmas, (3) scripting with pedagogical pause points, (4) video production, and (5) evaluation and refinement. Experimental results demonstrate that students exposed to scenario-based videos significantly outperformed those in traditional instruction in moral awareness, decision-making, and behavioral intention (p < 0.05). The study proposes and empirically supports a pedagogical framework and provides practical implications for integrating scenario-based video design into moral education, supporting the development of students’ ethical reasoning and behavioral competencies in digitally enriched learning environments.