This article reports the preparation and research of poly(3-hexylthiophene) (P3HT)/[6,6]-phenyl C61-butyric acid methyl ester (PC61BM)/Zinc oxide (ZnO) UV-visible dual-band photodetectors (PDs). At room temperature, ZnO, PC61BM and P3HT films were deposited on the FTO substrate using radio frequency magnetron sputtering technology and sol-gel technology respectively. A selective planar heterojunction organic photodetector was prepared using p-type polymer P3HT and n-type fullerene acceptor PC61BM as double active layers. Controlling phase separation in a binary complex system of donor and acceptor to improve hole extraction efficiency. This heterojunction has good UV-visible detection capabilities. Under a 2 V bias condition, the PD has a UV-visible dual-band response, with a peak at 380 nm of 0.072 A/W, and high wavelength selectivity. This demonstrates a facile method to prepare an organic-inorganic composite photodetector with high performance.