The objective of this paper presents the improvement of vector control inverter for PV water pumping system implement by DSP controller. A field oriented controlprinciple is used in control by changing a magnetizing current (Ids) follow a torque producing current (Iqs) in equality ratio resulting to the ratio of currents are constant.The efficiency of the motor pump is better than the magnetizing current constant. An adjustment of the magnetizing current follows light insolation that means themagnetic flux of motor pump are controlled, so the coreloss are reduced. The experiment results prove the concept of the constant ratio control between Ids and Iqs in order to optimum slip that the efficient of the water pumping system supplied by the photovoltaic arrays are increased. The system consume the maximum power fromPV every light intensity level.