In this paper, charge storage and its dynamics in positively corona char ged polytetrafluoroethylene（PTFE） film electrets have been studied. It is foun d that from room temperature to 100℃ and from about 150℃, especially from 180 ℃ to higher temperatures, slow retrapping controls the transport of detrapped c h arge; however, from about 100℃ to 150℃ the fast retrapping plays a dominant ro le. The increase of the initial surface potential will lead to a significant decay of charge density, so by means of properly controlling the charging parameter an d the heat treatment process we can get positively and negatively charged PTFE f ilm electrets with the same charge density, which not only have a similar charge storage life but also an outstanding charge storage stability. 