Objective To investigate the effects of Yiqi Huoxue Lishui formula ( YQHXLSF ) on mitochondrial morphology and function in heart failure (HF) model rats, via activation of the AMP-activated protein kinase ( AMPK) / peroxisome proliferator-activated receptor gamma coactivator ( PGC ) 1α signaling pathway. Methods The HF model was surgically induced in rats via ligation of the left anterior descending coronary artery, followed by a regimen of food restriction and forced exhaustive swimming. Postoperatively, rats were divided randomly into sham, model, trimetazidine (TMZ), YQHXLSF medium-dose, and YQHXLSF high-dose groups. After 4 weeks of treatment, cardiac function was assessed using echocardiography, hematoxylin-eosin and Masson staining. Reactive oxygen species (ROS) levels, mitochondrial ultrastructure, and functional changes were detected. Expression levels of AMPK/ PGC-1α pathway proteins were measured by Western blot, and mRNA expression and mitochondrial DNA (mtDNA) replication levels were evaluated by real-time polymerase chain reaction. Results YQHXLSF significantly improved cardiac function parameters (P<0. 05), attenuated myocardial fibrosis, and reduced ROS levels (P< 0.01). It also enhanced mitochondrial respiratory chain enzyme activity ( P< 0. 01) and membrane potential, and increased ATP content (P<0. 01). Western blot and RT-PCR Results showed that YQHXLSF upregulated the protein and mRNA expression levels of p-AMPK, PGC-1α, NRF-1, and TFAM, and promoted mtDNA replication ( P<0. 01). Conclusions YQHXLSF improves cardiac function and myocardial fibrosis, reduces ROS levels, augments ATP synthesis in rodent models of heart failure through preserving mitochondrial structural integrity and functional homeostasis, stimulating mitochondrial biogenesis, and fine-tuning energetic metabolism within mitochondria. The activation of the AMPK/ PGC-1α signaling axis appears to serve as a fundamental mechanism underlying these observed effects.