OBJECTIVES: The cancer knowledge gap represents a significant disparity in awareness and understanding of cancer-related information across different demographic groups. Leveraging Artificial Intelligence-Generated Content (AIGC) offers a promising approach to personalize health education and potentially bridge this gap. This study aimed to evaluate the potential of AIGC to bridge the cancer knowledge gap, assessing the roles of health self-efficacy as a mediator and educational level as a moderator in this relationship. METHODS: A 6-month longitudinal study was conducted using online surveys distributed to undergraduate students in non-medical disciplines at one university and graduate students in medical specialties at another university in China. The study assessed the frequency of AIGC use, health self-efficacy, and cancer knowledge at two time points. RESULTS: The results indicated that AIGC use significantly enhanced cancer knowledge levels and health self-efficacy over time. Educational level notably moderated the effects of AIGC use, with non-medical undergraduate students showing greater gains in knowledge and self-efficacy. Additionally, health self-efficacy mediated the relationship between AIGC use and cancer knowledge, underscoring the importance of health self-efficacy. The study confirms the efficacy of AIGC in narrowing the cancer knowledge gap and enhancing health self-efficacy, particularly among students with lower initial medical knowledge. CONCLUSION: These findings highlight the potential of integrating AIGC tools in cancer education and public health interventions, particularly for individuals at different educational levels. By tailoring digital health resources to varying educational needs, these interventions could enhance cancer knowledge acquisition, improve health self-efficacy, and contribute to better cancer prevention and control outcomes.