This study examined the unified model of phonological transfer in English reading comprehension and the mediating effects of bilingual decoding skills. Grade 4 Chinese Mandarin learners of English (N = 256) completed a series of tests including tone and stress sensitivity, Chinese and English segmental phonological awareness, Chinese and English word decoding, and English reading comprehension. Results indicated that (1) the cross-language contribution of L1 (Chinese) phonological awareness to L2 (English) reading comprehension occurred at both segmental and suprasegmental levels; (2) the final model, which incorporated bilingual decoding skills as mediators between phonology and English reading comprehension, significantly predicted English reading comprehension; (3) suprasegmental phonological awareness, segmental phonological awareness, and decoding skills could be transferred to facilitate L2 reading comprehension. Together, these findings confirm the robustness of the unified model in L2 reading comprehension and underscore the importance of segmental phonological awareness and decoding to explain prosodic transfer in English reading comprehension.