Resistance exercise is a widely used exercise modality for enhancing muscle strength and hypertrophy. However, the molecular mechanisms mediating acute resistance exercise-induced muscle protein synthesis have not been completely understood. In this article, we reviewed the hormonal responses and intramuscular molecular signaling systems involve in muscle protein turnover during and after acute resistance exercise, as well as the possible molecular mechanisms by which amino acids mediate post-exercise muscle protein synthesis from current literature. Acute resistance exercise is recognized as a strong stress to both human body and muscle cell. In order to cope with this physiological stress, a series of hormonal responses and intramuscular signaling transduction systems, which involve in muscle protein synthesis and growth, are initiated during and after acute resistance exercise. During resistance exercise, the catalytic hormones and intracellular signaling systems override the protein synthetic effect, thereby reducing net protein synthesis in skeletal muscle. In the post-exercise period, the sustained mechanical stress-induced protein synthesis and the releasing of anabolic hormones synergistically activate protein synthesis and muscle hypertrophy in skeletal muscle via activating protein synthetic signaling systems and satellite cell proliferation. Furthermore, after resistance exercise, the ingestion of supplements containing protein or amino acids is capable of obtaining greater muscle protein synthetic effect during postexercise recovery.