A pixel structure includes a scan line, a data line, a gate electrode, a semiconductor layer, a source electrode, a drain electrode including a comb-shaped part surrounding the source electrode and a connecting part, and a pixel electrode electrically connected to the drain electrode. The scan line and the data line are arranged intersectedly and electrically insulated from each other. At least a portion of the source electrode and the drain electrode are disposed on the semiconductor layer. At least one branch of the comb-shaped part extends outside one side of the gate electrode to form a protrusion part. The connecting part extends from the comb-shaped part beyond the other side of the gate electrode. The protrusion part and the connecting part aligned with the margin of the gate electrode have a first width and a third width respectively, wherein the first width substantially equals to the third width.