ZnO nanoroods/poly (MEH-PPV) hybrid solar cells are fabricated and their properties are discussed. In order to improve the absorption of sunlight, a layer of 3,4,9,10-perylenetetracarboxylic dianhydride(PTCDA) is inserted between ZnO nanorods and MEH-PPV, and cells with the structure ITO/ZnO nanorods/PTCDA/MEH-PPV/Au are prepared with different thickness values of PTCDA. After introducing PTCDA, the devices show a strong and broad absorption in visible region, which increases the number of photo-induced excitons and thus results in an enlarged photocurrent. When the thickness of PTCDA is 40 nm, we can observe the smooth morphology of thin layer surface, and achieve the best performance of the device.