The composite insulating material composed of polytetrafluoroethylene (PTFE) film and silicone oil is widely used in dry-type high voltage apparatus. Though PTFE film is a key component of composite insulation, the spatial charge distribution of it is not clear yet. However, the existing researches prove that the space charge has a great influence on insulation discharge. Therefore, the space charge distributions of PTFE film at different temperatures are measured by electroacoustic pulse method. The results show that the negative space charge is easy to accumulate in the PTFE medium under the applied DC electric field. Secondly, the increase of temperature helps to accelerate the rate of space charge dissipation in the PTFE medium and dissipate the charge. However, the increase of temperature will also lead to the increase of space charge injection and accumulation of PTFE, and might promote the ionization of impurities in the medium, and lead to the accumulation of lots of space charge in the PTFE medium. Therefore, aiming at eliminating as much space charge a possible,it is recommended that the PTFE insulation medium should avoid to be operated at high temperature.