In this paper, polycrystalline perovskite (CH₃NH₃PbI_xCl_3−x) photodetectors with a structure of Au/CH₃NH₃PbI_xCl_3−x/Au are prepared and are shown to have good performance. The measured electrical parameters demonstrate that the current behavior of the perovskite photodetectors is dependent of work temperature from 300 K to 350 K. We find that only space charge limited conduction mechanism fits the current–voltage (I–V) curves under small external voltage (0.1–0.7 V) both under darkness and illumination. The lattice vibration scattering plays the major role in the dark, leading to a decreased current as the temperature increases under the same external voltage, and an enlarged current increasing with the temperature is due to the leading role of the ionized impurity scattering. At each temperature, the rising slope of the I–V curves decrease with the increase of voltage both under dark and illumination. The values of on/off ratio, responsivity and detectivity increase with the measured temperature, which indicates that the polycrystalline perovskite photodetector can work with better performance at high temperature. However, the stability in the dark gradually becomes weak as the temperature increases, especially at 330 K and above.