Generative artificial intelligence (GenAI) is increasingly playing a pivotal role in cultural heritage activation and engagement which has not been adequately understood. This study explores the role of GenAI in activating and engaging cultural heritage with a focus on how GenAI can benefit restoration, storytelling, and interaction with the cultural heritage at the Dunhuang Mogao Cave Exhibition using a direct observation method. It shows that GenAI technologies such as image-to-video, image rectification and inpainting, text-to-speech, and temporal sequence generation can boost dynamic activation and interactive narrative in the exhibition. This leads to the conclusion that GenAI is a transformative tool in the activation and engagement of cultural heritage.