Compared with the traditional image intensifier with phosphor screen readout, the photon-counting imaging detector with charge induction readout is more beneficial in several aspects (e.g., good imaging properties and time resolution) to astronomy, reconnaissance, bioluminescence, and materials research. However, the annealing temperature during the tube-making process can affect the properties of the Ge film, and consequently impair the performance of the detector. Therefore, the influence of annealing temperature on Ge film and on the detector is studied in order to determine the crucial parameters. The Ge films are prepared on ceramic and quartz glass by the use of an electron gun. They are analyzed by scanning electron microscope (SEM), high-resistance meter, and X-ray diffraction (XRD). The results show that the optimum substrate and annealing temperature are ceramic plate and 250 ℃, respectively.