Objective The current study aimed to explore the role and the molecular mechanism of Shen'ge powder in cardiomyocyte hypertrophy in chronic heart failure (CHF). Methods Sprague-Dawley rats were selected for the study and divided randomly into four groups: control, model, Shen'ge powder, and fasudil group. An inverted microscope was used to determine the diameter of cardiomyocytes in each group. The survival and apoptotic rate of cardiomyocytes in each group was determined by the tetrazolium dye MTT 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry, respectively. The messenger RNA levels and protein expression of RhoA, Rho-associated coiled-coil forming protein kinase (ROCK), myosin light-chain phosphatase (MLCP), and myosin light-chain kinase (MLCK) were determined by quantitative reverse transcription-polymerase chain reaction and Western blot analysis, respectively. Results CHF increased the diameter and apoptotic rate of cardiomyocytes and decreased the survival rate of cardiomyocytes. The levels of RhoA, ROCK, and MLCK were increased significantly in CHF model rats, and the level of MLCP was decreased. After treating with Shen'ge powder, the expression of RhoA, ROCK, and MLCK decreased dramatically and the expression of MLCP increased. Conclusion Shen'ge powder could reduce cardiomyocyte hypertrophy in CHF by regulating the Rho/ROCK signaling pathway.