GaN epilayers were grown on sapphire substrates by metal-organic chemical vapour deposition. Metal-semiconductor-metal photoconductive detectors were fabricated using this material. The photocurrent properties ofthe detectors were measured and analysed. The spectrum response shows a high sensitivity in the wavelength regionfrom 330 to 360nm, with a peak at 358nm and a sharp cutoff near 360nm. The maximum responsivities at 358nmwere 700A/W (2V) and 7000A/W (30V). The relationship between responsivity and bias indicates that the responsivityincreases linearly with bias until 30V. The influence of the spacing between two electrodes on the detector responsivitywas also studied.