A tri-gate pixel structure includes three sub-pixel regions, three gate lines, a data line, three thin film transistors (TFTs), three pixel electrodes, and a common line. The gate lines are disposed along a first direction, and the data line is disposed along a second direction. The TFTs are disposed in the sub-pixel regions respectively, wherein each TFT has a gate electrode electrically connected to a corresponding gate line, a source electrode electrically connected to the data line, and a drain electrode. The three pixel electrodes are disposed in the three sub-pixel regions respectively, and each pixel electrode is electrically connected to the drain electrode of one TFT respectively. The common line crosses the gate lines and partially overlaps the three gate lines, and the common line and the three pixel electrodes are partially overlapped to respectively form three storage capacitors.