The present disclosure provides a photoelectric conversion array substrate and a photoelectric conversion device, and the photoelectric conversion array substrate includes: a base substrate; a thin film transistor located on the base substrate and including a gate, a gate insulating layer disposed on the gate, an active layer disposed on the gate insulating layer, and a source electrode and a drain electrode located on the active layer; a photodetection unit located on the base substrate and including a signal output electrode, a photosensitive layer and a transparent electrode that are located on the base substrate, the signal output electrode electrically connected to the drain electrode, wherein an orthographic projection of the transparent electrode on the base substrate is located within an orthographic projection of the photosensitive layer on the base substrate; a first protective layer covering the source electrode and the drain electrode.