This paper designed a solar water tank with dimension of 80cm(height)×40cm(width) ×40cm(length) and the slotting inlet and direct inlet to study discharging performance of tank by presenting some experiments and simulations. The Ri number and the discharging efficiency were introduced to investigate the performance of the different inlet-tanks. The discharging efficiency was introduced to evaluate the thermal performance of the tank with different inlets. The result indicated that slotting inlet improved the efficiency of thermal stratification effectively and promoted discharging performance obviously. The discharging efficiency of slotting inlet was 7% higher than the direct inlet with the flow rate of 5L/min and the gap increased to 25% when the flow rate is 15L/min.