Ag-ZnO-Ag X-ray detectors based on ZnO film and nanowires are both fabricated in this paper. Results of continuous X-ray radiation measurement show that the two detectors have high responsivity: the responsivity of the ZnO film device is about 0.12 μC/Gy under a 100 V bias voltage, and that of the ZnO nanowires device is about 0.15 μC/Gy under a 50 V bias voltage. Surface effect due to the absorption and desorption of oxygen on the ZnO surface, which makes the carrier lifetime increase, is decisive to the high responsivity. ZnO film and nanowires have their potential applications in the X-ray dose rate measurement.