A display panel, a manufacturing method thereof and a display device are provided. The display panel includes an array substrate and an opposing substrate which are disposed opposite to each other; the array substrate includes a first base substrate and a source electrode, a drain electrode and an active layer which are disposed on the first base substrate, and a passivation layer disposed on the source electrode, the drain electrode and the active layer; the opposing substrate includes a second base substrate and a gate electrode disposed on the second base substrate; the active layer includes a source electrode region, a drain electrode region and a channel region between the source electrode region and the drain electrode region, the gate electrode is disposed opposite to and spaced apart from the passivation layer at a position where the channel region is located.