The present invention provides a thin film transistor, an array substrate and a display device. The thin film transistor includes an active layer, a source electrode and a drain electrode. The active layer includes a source electrode contact region, a drain electrode contact region, and a semiconductor channel region arranged therebetween. A conductive layer is provided on the semiconductor channel region and is spaced apart from the source electrode and the drain electrode. The semiconductor channel region is U-shaped when viewed in a plane view of the pixel thin film transistor, and the source electrode includes a U-shaped part corresponding to the U-shaped semiconductor channel region. The conductive layer includes at least one conductive part, and the at least one conductive part is arranged between one end of the drain electrode and the U-shaped part of the source electrode.