The objective of this work is to study experimentally the characteristics of jet pump. Suction head, driving air pressure and the percentage of the distance between throat section and nozzle are recorded. The effect of each parameter on the pump performance is investigated, in order to have a better understanding about the behavior of such pump under various conditions. A simple geometry jet pump was designed, developed and tested. The experiments show that we should be careful in increasing the suction head, and stability must be considered between the suction head and the driving air mass flow rate. While the effect of increasing P_a will stop at certain maximum of the ratio of the mass flow rate of water to air (M), that is any increase in P_a will meet no change in M. While increasing S/D_th will leads to decrease in the percentage of M because the optimum S/D_th = 0.5 so that at this value we will have the best performance and any other values for S/D_th the percentage M will decreases, but this effect is not so clear and it could be neglected. The pump performance is not so sensitive with the change of S/D_th after S/D_th = 0.5. Also this information will help improving and extending the use of the jet pump in many practical applications.