Cyclosporine A (CSA) is an polypeptide immunosuppressive agent with good immunosuppressive activity. It is widely used in organ and tissue transplantation. Due to its poor oral absorption, great individual differences in metabolism, its concentration and efficacy is related to toxicity and narrow treatment window, monitoring the blood concentration of CSA is required. In addition, there are many metabolites of CSA in vivo, and in vitro experiments show that the metabolites of CSA have different activities. Many commercialized regiments based on different principles and methods have been used to detect CSA blood concentration, thus to chose a valid method has become a major issue in clinic and laboratory. In this paper, we review current methods for monitoring CSA blood concentration and show the genes that associated with CSA metabolism. We hope it will be helpful to interpret the CSA concentration in clinic and laboratory.