Devices with the structure of ITO/Pentacene/C60/Al were prepared. Then, in order to enhance the performance of these cells and study the mechanism of the cathodic buffer layer, bathocuproine (BCP) of different thickness were inserted between C60 and Al. When inserting 10 nm BCP, the power conversion effciency of the cell is as high as 0.46%. On this basis, bathophenanthroline (Bphen) and 3, 4, 9, 10-Perylenetetracarb-oxylicdianhydride (PTCDA) are used instead of BCP, so as to compare and discuss the effects on the performance of the solar cells caused by the electron mobility and optical absorption properties of the cathodic buffer layers. As the electron mobility of Bphen is two orders of magnitude higher than that of BCP, the efficiency of devices with Bphen as the buffer layer was improved to 0.56%. Furthermore, the absorption spectrum of devices was obviously enhanced by inserting PTCDA material which has large absorption in visible light region, and the highest current density of such device was enhanced to 5.97 mA/cm2 and the efficiency was 0.87%.