Science fiction film subtitle translation, situated at the intersection of linguistic conversion, technical constraints, and fictional world construction, represents a unique translation challenge. This paper explores the theoretical frameworks, practical strategies, and emerging trends in sci-fi film subtitle translation by analyzing recent academic achievements and case studies including the Star Wars series and The Wandering Earth series. The study identifies four primary challenges facing sci-fi film subtitle translators: neologism and terminology management, handling scientific and technological discourse, cultural specificity within fictional contexts, and multimodal constraints. Drawing on Relevance Theory, Functional Equivalence Theory, and Multimodal Discourse Analysis, it evaluates translation strategies including transfer, compression, paraphrase, and creative adaptation. The research further examines the impact of modal differences between subtitling and dubbing, and the emergence of human-machine hybrid translation models. The findings indicate that optimal sci-fi film subtitle translation requires balancing source text fidelity with target audience comprehensibility, while appropriately managing the genre's inherent tension between scientific plausibility and imaginative fiction. The study concludes by proposing a comprehensive framework for sci-fi film subtitle translation practice and identifying future research directions in this rapidly evolving field.