Abstract: Yangtze finless porpoises are a class of secondary aquatic mammals whose senses of sight, smell and taste have been degraded in order to adapt to aquatic life, and their daily activities are highly dependent on the auditory system. Among the many factors affecting auditory function, environmental noise has been of great concern. To investigate the effect of environmental noise on the auditory function of Yangtze finless porpoise, this study sequenced and analyzed the blood tissues collected in natural waters (with the effect of environmental noise) and ex-situ waters (without the effect of environmental noise) by RNA-seq technology, and identified a total of 4613 DEGs, and further screened 81 DEGs related to auditory and noise-induced hearing loss for in-depth analysis. Among them, inflammation and immunity genes, antioxidant genes and heat shock protein genes were up-regulated under the influence of environmental noise. GO analysis showed that 81 genes were significantly enriched in entries related to ear and inner ear development, antioxidant activity, etc. KEGG analysis showed that 81 genes were mainly enriched in signal transduction, immune system and cell growth and death related pathways. The results suggest that environmental noise may affect the auditory function of Yangtze finless porpoise by inducing inflammatory response and cell death, oxidative stress, etc., while Yangtze finless porpoise prevent further impairment of auditory function by inhibiting inflammation and cell death, antioxidant, etc. This study provides a new perspective to investigate the molecular mechanism of the auditory system of Yangtze finless porpoise in response to environmental noise, and provides an important theoretical reference for the conservation of Yangtze finless porpoise.