Silicon nanowire (SiNW) arrays were grown directly on a P type Si substrate, pre-deposited with gold catalyst, and then made into solar cell for photovoltaic characteristic measurement. Different growth conditions of SiNWs, including variation of the flow rate ratio of SiH 4 versus N 2, and the thickness of Au film, which can be sputtered into different size of nanoparticles, will be made in order to obtain an optimum photovoltaic conversion efficiency. The morphologies and crystalline structure of the nanowires are studied by SEM, TEM and XRD. The SiNW array surface is shown to have good antireflection property, and is expected to raise light absorption and short circuit current. The photovoltaic performance of the solar cells with SiNWs grown at different conditions is measured and discussed. More effort is still needed to raise the performance of SiNW solar cells.