This study evaluates the effectiveness of ChatGPT 4.0 in translating Chinese idioms into English subtitles from the perspective of cognitive translatology, focusing on the case study of the TV drama The Story of Minglan, which is adapted from an online novel. With the evolution of AI in translation, assessing the quality of subtitles, especially for content rich in cultural metaphors, becomes crucial. By analyzing ChatGPT’s translations against traditional machine translation tools, and integrating both BLEU scores and manual evaluations, this research aims to understand ChatGPT’s ability to capture metaphorical meanings and cultural nuances. Findings suggest ChatGPT outperforms other AI models in translating idioms, demonstrating a strong capability to recognize implicit metaphors and successfully achieving category conversion between languages. This study highlights ChatGPT 4.0’s potential in subtitle translation, advocating for its use complemented by human editing to bridge cultural gaps and enhance the global sharing of audiovisual content.