Last subprime financial crisis of 2007 did return to the stage the issue of banking risks, particularly liquidity risk. This risk must be currently managed by more sophisticated methods and more attention. The main objective of this research is to analyze the liquidity of Moroccan banking sector, because, ultimately, all the proposed routes are articulated around it. Thus, monetary policy tends to naturally control the increase in the volume of money available to agents nonbank sector to make it compatible with the rate of change in the overall supply of goods and services. This article is based on a retrospective analysis provides some answers of the various underlying causes of bank liquidity in Morocco.