In the following, a work was conducted to evaluate the performance of PV/T system when using Nano fluid as working fluid. The used Nano fluid consists of Al2O3 50 nm suspended in water as base fluid. Firstly, Tests were performed with different flow rates of water as a cooling agent, and then volume concentrations ratios (0.05, 0.075, 0.1, 0.2, .03) were used as a working fluid at the highest flow rate. The results showed that using Nano fluid increases the combined performance of PV/T by 74 and 56% at volume concentration 0.1% V Concentration. The optimum flow rates achieved in the experiment was 1.2 l/mini. Finally using Nano fluid increases the efficiency of PV/T system significantly.