The photovoltaic (PV) pumping system is a widely used application in Mauritania to ensure the water supply in rural area for populations needs. The system is composed of a PV generator, a DC/DC converter, a DC/AC inverter, a BLDC motor and a centrifugal pump. Study in this article we study with simulation in Matlab/ Simulink environment the performances of the PV pumping system taking into account the climate parameters (solar irradiance, and ambient temperature), and the effect of the total manometric head (HMT) on the pumped flow rate. In addition it also counted the electrical energy and flow rate of the each climatic parameter. Two mathematical motor -pump models for PV application, were proposed in this article to contribute in the studies of PV pumping sizing. These models link directly the operating current to the voltage and electrical power to the flow rate of the pump versus total head.