A novel diamond UV photodetector with a transparent Ag nanowire (NW) electrode was fabricated. A transparent Ag NW network was spin-coated on single crystalline diamond to form a Schottky contact, which had a barrier height of about 1.37 eV obtained by XPS measurements. Meanwhile, multilayered metals of Au/Pt/Ti were evaporated on the diamond sample to form ohmic contacts. Compared to a Au/Pt/Ti-Au/Pt/Ti diamond photodetector, the Au/Pt/Ti-Ag NW diamond photodetector exhibited relatively high responsivity under 220 nm (18 mA W−1), high linear dynamic range (41 dB), and short response time (0.12 s for rise time, 0.56 s for decay time). In particular, the Au/Pt/Ti-Ag NW diamond photodetector displayed high photocurrent of about 200 pA at zero-bias, indicating its potential for creating self-powered devices.