To investigate the ameliorative effect of Lactobacillus rhamnosus GG (LGG) on cardiorenal injury in chronic heart failure (CHF) rats, a CHF rat model was established by ligating the left anterior descending branch of the left coronary artery. The rats were then randomly divided into the sham operation group, LGG group, CHF group, and LGG intervention group. After 8 weeks of LGG intervention, echocardiography was performed to assess rat cardiac function, and levels of serum N-terminal pro-B-type natriuretic peptide (NT-proBNP), serum creatinine (Scr), and blood urea nitrogen (BUN) were measured. The contents of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), glutathione peroxidase (GSH-Px), malondialdehyde (MDA), and superoxide dismutase (SOD) in renal tissues were determined. Additionally, changes in the expression levels of TNF-α, IL-6, MCP-1, and IL-10 were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR), and the pathological changes of renal tissues were observed. The results showed that LGG can repair the cardiorenal dysfunctions caused by CHF. After LGG intervention, the mRNA expression levels of TNF-α, IL-6, and MCP-1 decreased by 13.92%, 15.20%, and 15.58%, respectively, whereas that of IL-10 increased by 22.21%. The TNF-α and IL-6 contents in renal tissues decreased significantly by 18.67% and 25.92%, respectively. Furthermore, SOD and GSH-Px activities increased by 31.73% and 43.14%, respectively, after LGG intervention, and the MDA content decreased by 14.85%. The pathological severity of renal tissue was also improved. In conclusion, LGG can repair renal dysfunction by alleviating oxidative stress injury and inflammatory response. These findings can provide a theoretical foundation for developing functional products against CHF-related renal injury.