This study aimed to investigate the effects of heat stress (HS) on growth performance, carcase characteristics and rumen-muscle axis of Hu sheep and to explore the underlying molecular mechanisms of the actions by establishing a heat-stressed Hu sheep. The results showed that HS significantly decreased growth performance and carcase characteristics, altered metabolic enzyme activities, and induced a shift in muscle energy metabolism towards a more glycolytic and less oxidative fibre type in the longissimus dorsi (LD) muscle (p