An aryl amine polymer is provided which contains a specific repeat unit, its use in preparing an organic semiconductor material which contains the aryl amine polymer and an additional specific compound and in the preparation of organic light emitting devices (OLED), organic thin film transistors (TFT) and so on, along with an organic TFT including a substrate, an organic semiconductor layer which contains the organic semiconductor material and is located overlying the substrate, an electrode pair of a source electrode and a drain electrode; and a third electrode.