We have fabricated an organic deep ultraviolet photodetector (PD) using PEDOT:PSS (PH 1000) as a transparent anode. NPB and PBD were employed as electron donor and acceptor, respectively. The PD exhibits a dark current of $0.0829\mathrm{\mu A}/{\mathrm{cm}}^2$ and a photocurrent of $85.3\mathrm{\mu A}/{\mathrm{cm}}^2$ at $-12\mathrm{V}$ under $280\mathrm{nm}$ light illumination with an intensity of $0.488\mathrm{mW}/{\mathrm{cm}}^2$. A high response at $248–370\mathrm{nm}$ with its peak of $0.18\mathrm{A}/\mathrm{W}$ at $280\mathrm{nm}$ and a detectivity of $1.1\times {10}^{12}\mathrm{cm}{\mathrm{Hz}}^{1/2}{\mathrm{W}}^{-1}$ were achieved. The more detailed mechanism of harvesting high performance and the dependence of photocurrent density on illumination intensity are also discussed.