The purpose of oral floating drug delivery systems (FDDS) drug should be hold the drug in the gut and stomach and applicable for drugs with poor solubility and low stability in intestinal fluids. This fdds is also known as Hydro dynamically Balance system (HBD). This was to elaborate with suitable method enclosing of drug floatation to attain gastric holding. By the help of the FDDS increase the time in gastric region and improve bioavailability. The current development of floating drug delivery system mention the physiological and variable affecting gastric holding with drug delivery system of non-effervescent system including the doses form used for gel forming and matrix forming. Effervescent system with prepare that when it arrives in abdomen carbon dioxide released. Review is assembling the in-vitro technique and in-vivo technique for performance and use of drug floating system.