A transistor structure disposed on a substrate includes a gate electrode, a gate insulating layer overlapping the gate electrode, a channel layer overlapping the gate electrode, and a plurality of first electrodes and a plurality of second electrodes overlapping the gate electrode. The gate insulating layer is disposed between the channel layer and the gate electrode. Besides, the gate insulating layer is located among the first electrodes, the second electrodes, and the gate electrode. The first electrodes and the second electrodes are alternately arranged along a first direction. Each of the first electrodes has a first width along the first direction. Each of the second electrodes has a second width along the first direction. A ratio of the first width to the second width ranges from 2 to 20. A driving circuit structure having the transistor structure is also provided.