Cadmium is a toxic heavy metal contributing to lower male fertility, while swim bladder extracts may have a protective effect against reproductive toxicity caused by cadmium due to its various biological activities such as antioxidant and anti-aging. Herein so as to investigate the ameliorative effects of ethanol-soluble sturgeon swim bladder hydrolysate (SSBH-ES) on reproductive toxicity caused by cadmium in male mice and to explore its mechanisms involved. The results revealed that SSBH-ES could effectively alleviate Cd-induced weight loss and testicular mass loss in mice, restore testicular tissue structure, increase antioxidant levels and energy enzyme activities, and maintain serum hormone levels. Moreover, SSBH-ES could preserve the balance of gut microbiota by elevating the levels of Bacteroides, Paramuribaculum and Mucispirillum, while reducing the levels of Crytobacteroides Mailhella and Prevotella with these changes correlating with variations in reproductive indicators. These results demonstrated the beneficial effects of SSBH-ES supplementation on gut microbiota and male reproductive health, providing new insight for the therapeutic potential against Cd-induced testicular toxicity.