The present invention provides a low-temperature polysilicon thin film transistor and a manufacturing method thereof, an array substrate and a manufacturing method thereof, and a display device. The present invention is related to display technology. The low-temperature polysilicon thin film transistor comprises: an active layer disposed on a substrate, and a source electrode and a drain electrode respectively connected to the active layer, the active layer comprises a source contact region, a drain contact region, and a semiconductor region disposed between the source contact region and the drain contact region, the source contact region and the drain contact region are both conductive, both of the source contact region and the drain contact region include a semiconductor substrate and ions distributed in the semiconductor substrate, the source electrode covers the source contact region directly, and the drain electrode covers the drain contact region directly.